world architecture

Republic of Zimbabwe, Africa
The ruins of Great Zimbabwe Bantu forstone house stand about 17 miles 30 kilometers southeast of the modern provincial capital, Masvingo, and east of the Kalahari Desert between the Zambezi and Limpopo Rivers. They cover about 200 acres 80 hectares. The largest of about 300 such sites in the region, Great Zimbabwe was once the greatest city in sub-Saharan Africa. Misguided and racist Victoriansand others sincethought Africans incapable of such sophistication, and they therefore incorrectly concluded that ancient Phoenicians, Romans, or Hebrews created the amazing structures. The British archeologists David Randall-MacIver 1905 and Gertrude Caton-Thompson 1929 carried out excavations and discovered that the place was indeed indigenous African in origin. Their conclusions were confirmed by further investigations made by R. Summers, K. R. Robinson, and A. Whitty in 1958. The builders were ancestors of the modern Shona people of Zimbabwe. Even in ruin, Great Zimbabwe has been calledremarkable,majestic,awe-inspiring, andtimeless when intact, it was an architectural masterpiece. Now known as the Great Zimbabwe National Monument, the site was inscribed on UNESCOs World Heritage List in 1986. The area was first settled by Bantu-speaking farmers, perhaps in the second and third centuries a.d. A second phase of occupation began about a.d. 330. The grasslands in the foothills of the Mashonaland plateau provided excellent pasture, and between 500 and 1000 the cattle-herding Gokomere people overran and absorbed the earlier inhabitants. Rich local gold deposits were later utilized, and it seems that some stone walls were built toward the end of that period. Scholars remain divided on how the Mwenemutapa of Great Zimbabwe attained their high lifestyle and widespread influence. Some believe that it came from cattle wealth and coastal trade in gold with contacts as far afield as India and China. Others suggest that a powerful politico-religious ideologygave them a competitive edge over neighbors so that they could coerce the human resources needed to build their city. But as yet there is no evidence that their success depended upon a single factor. Anyway, between the thirteenth and fifteenth centuries Great Zimbabwe, capital of the wealthiest society in the region, dominated the area that now encompasses eastern Zimbabwe, Botswana, Mozambique, and South Africa. There were three main groups of buildings: they are now designated the Hill Complex, the Great Enclosure, and the Valley Complex. The approximately oval Hill Complex ca, a.d. 1250 was clearly a defensible retreat. Measuring about 330 by 150 feet 100 by 45 meters, it crowned a steep rocky prominence 260 feet 80 meters above the valley at the north end of the settlement. It comprised several enclosures connected by a network of narrow walled alleys. Drystone walls of dressed rectangular granite blocks linked the large natural outcrops to fortify a number of areas. The large western enclosure, its 20-foot-high 6.1-meter perimeter wall nearly 17 feet thick 5 meters, is thought to have been a religious precinct. The smaller eastern enclosure was probably residential, perhaps for the royal court or the chief shaman. At least three routes approached the hill from the west. Most of the buildings in the Great Enclosure at the southern edge of the site date from the early fourteenth century its elliptical perimeter wall was first built nearly 100 years later and subsequently restored a number of times. The 16-foot-thick 5-meter, 36-foot-high 11-meter wall, its drystone faces meticulously built from dressed granite the core is rubble, contains a space 840 feet 255 meters in circumference and 330 feet 100 meters across there are three unfortified doorways. The enclosure embraced a few elite residences, including the royal compound and an enigmatic 33-foot-high 10-meter conical towera solid, granite affair with a 16-foot about 5-meter base diameter. There is also a smaller tower. The rambling Valley Complex, between the other nodes of the city but closer to the Great Enclosure, dates from the early fifteenth century. It once comprised several stone-walled irregular yardsone writer calls it anarchipelagoaround the houses of more important citizens. However, most families probably lived in densely packed dhaka mud huts with thatched roofs, clustered between theseislands. More small towers, possibly of religious significance, dotted the area. The surviving masonry strongly suggests that the Zimbabweans independently evolved a technology that optimized immediately local resources. Their construction system began as a simple response to necessity and ended with sophisticated work that expressed joy in building, as it employed herringbone, chevron, and other decorative bonding, all made without mortar. Great Zimbabwe was fully occupied for about 300 years, but by the end of the fifteenth century it lay abandoned. Although grazing land was at first abundant, the poor soil could not have supported crops enough to sustain the citys increasing populationby the late fourteenth century it may have reached 18,000so some food necessarily would have been imported. By the fifteenth century Great Zimbabwes power had begun to fade, coincident with the rise of Torwa and Mutapa, the neighboring states. The reasons for its demise are unclear, but a familiar pattern is likely. Urban growth overtaxed the immediate environment, and the pressure put on resources by people and herds alike probably led to decline, resulting in social, economic, and political instability, and finally fragmentation. Many cultures have ended thus, not with a bang but a whimper.

Northumberland, England
The most audacious building project among many initiated by the Roman emperor Publius Aelius Hadrianus known as Hadrian was the defensive rampart across the entire width of Britain that marked the northern frontier of the Roman Empire for almost 300 years. Started in a.d. 123 Hadrians Wall was about 73 miles 118 kilometers long, stretching from what is now the town of Wallsend Roman Segedunum on the River Tyne in the east to modern Bowness Roman Banna on the Solway Firth in the west. From there, seaward defenses, somewhat less substantial, turned south along the Cumberland coast for another 40 miles 65 kilometers. Spurred by his conquest of Gaul, Julius Caesar undertook a reconnaissance of Britain in 55 b.c. A full-scale Roman invasion took place in a.d. 43, when Claudius was emperor, and there followed decades of resistance by various local tribes. But Britain, soon known asthe food basket of Rome, was too rich a prize to surrender. Under the governor Petilius Cerealis, the legions marched north into the territory of the Brigantes and established a base at York Roman Eboracum in a.d. 71. About ten years later, they pushed forward into Scotland, creating a temporary frontier between the Rivers Forth and Clyde. They intended to consolidate their new conquests by constructing roads and forts caestra, but the northern tribes proved too warlike, causing the Romans to strategically withdraw. Hadrian, the adopted son of Trajan, reigned from a.d. 117 until 138. He loved to build: among his architectural schemes in and near Rome were his own tomb later known as the Castel Sant Angelo, the Pantheon, and a luxurious country villa at Tivoli. He was also an inveterate traveler and for over half of his reign he was away from Rome, mostly touring the eastern provinces and North Africa. On a visit to Britain in 122 he appointed a new governor, Aulus Pletorius Nepos, and in order to establish a presence in the far north, he commissioned the construction of the Wall toseparate the Romans from the barbarians. Work started the following year. As planned, the eastern sector between Wallsend and the River Irthing was to be a stone structure, about 10 feet 3 meters thick and 15 feet high to the rampart the parapet was 5 feet higher. As it was eventually built, the thickness along the wall varied faces were of dressed stone and the infill of rubble. From Irthing to Bowness a turf-and -timber wall, about 20 feet 6 meters thick at the base, was initially built and replaced with stone within a few years. Immediately south of the wallexcept in the craggy terrain across the Penninesthere was a continuous ditch Roman vallum, 10 feet 3 meters deep and 20 feet wide at the top, with a flat bottom 8 feet 2.4 meters wide. It was flanked, 30 feet away on each side, by wide earth mounds. These earthworks defined the southern limit of the military zonein effect, like a customs zone at any modern border. It was originally intended that the wall would be manned by patrols from small forts calledmilecastles at 600-foot 184-meter, the Roman stadium intervals. Military and logistical backup would come from established but widely spaced fortresses like Corbridge Roman Corstopitum, usually at the junction of principal roads. Plans changed during the eight years taken for the building. A total of seventeen forts, some for 1,000 foot soldiers e.g., Housesteads, Roman Vercovicium and others for elite, 500-strong cavalry regiments e.g., Chesters, Roman Aesica, were built at roughly evenly spaced locations along the wall. Each milecastle, serving as a controlled crossing place to the north, had a gate reached by stone causeways across the vallum. Each housed only about two dozen men. Between them, Hadrians Wall had two evenly spaced stone observation and signal turrets that were manned by legionaries from the milecastles. Construction was practically complete by a.d. 130, although some work seems to have continued for another eight years. Most of the labor was provided by ordinary soldiers of the three Italian legions then based in Britain, who moved about 1.7 million cubic yards 1.3 million cubic meters of turf and stone. The total garrison probably numbered about 12,000, mostly drawn from auxiliary legions raised in different provinces of the empire. It is clear that such a well-manned outpost was not intended merely for defense it was used to attack the hostile northern tribes. Moreover, Hadrians Wall identified Rome by creating a highly visible boundary. Because traders had to use the milecastles as crossing points to the unconquered territories beyond, and because there was a concentration of population, markets and other social structures developed in some areas. Hadrian was succeeded by Antoninus Pius, who in a.d. 139 commanded another advance into Scotland, reestablishing the frontier. The 37-mile-long 59-kilometer Antonine Wall was built around a.d. 142 between what is now Old Kilpatrick on the Clyde River and Carriden on the Forth. The 9-foot-high 2.75-meter turf-faced soil rampart stood on a stone foundation. There was a 40-foot-wide 12-meter vallum, 12 feet 3.7 meters deep on its north side. Small forts were located at about 400-yard 370-meter intervals. By about a.d. 155 the Romans again retreated from Scotland, to return only briefly between a.d. 159 and 163. Hadrians Wall regained its former importance the vallum, which had been partially filled, was finally reconstructed by about a.d. 208. Breached only three times during the remainder of the occupationin a.d. 197, 296, and 367it was retaken on each occasion and rebuilt where necessary to remain the frontier of Roman Britain until the last legions departed in a.d. 410.

Istanbul, Turkey
The great Church of the Holy Wisdom, known as Hagia Sofia or Sancta Sofia, in Istanbul, is the high point of Byzantine ecclesiastical architecture, remarkable for its revolutionary dynamic structural system and the ingenuity of a plan that subordinates liturgy to form. It was dedicated by the Byzantine emperor Justinian in December 537. Like many churches, it was built on the site of former sacred structures, some of which predated Christianity. The earliest church had been replaced in 361 by the timber-roofed basilica Megala Ekklesia. Damaged during religious riots in 404, this second building was restored eleven years later under Emperor Theodosius II, only to be burned down in another uprising in 532. Within weeks Justinian commissioned the great church of Hagia Sofia. He had been, crowned in 527. Despite the fall of the Western Empire to Germanic invaders in the late fifth century, Justinian ensured that his Eastern Empire survived. He and his wife, Theodora, reigned as unofficial joint rulers, together transforming Constantinople into a city that was universally admired and envied. Justinian employed the architects Anthemios of Tralles and Isidor of Miletus to build a church of great size and magnificence, sparing no expense. Materials were transported from all over his domain. Dressed marble was plundered from classical pagan buildings it is said that eight red porphyry columns were brought from the Artemiseion at Ephesus new stone came from the finest marble quarries in Phrygia, Egypt, Thessaly, and the Morean Peninsula. The interiors were decorated with mosaics of gold, silver, glass, marble, and granite tesserae. Because of the urgency, tradition has it, 1,000 masons and 10,000 apprentices worked on the building. It was completed in just twenty days under five years. There is a story, perhaps apocryphal, that upon, first visiting the completed church Justinian exclaimed.Oh Solomon! I have excelled you! The central dome, framed with forty brick ribs, is slightly elliptical, its base measuring 101 by 104 feet 30.3 by 31.2 meters. It springs from pendentives at 183 feet 54 meters above the floor and rises to 226 feet 67.8 meters. There is a window between the bases of each pair of ribs, and the resulting ring of light creates the illusion that the dome is poised in the air with little apparent support. The true massiveness of the masonry structure is replaced with a virtual building created from lightnot only because the penetrating rays of the sun constantly change in angle and direction, but also because of the scintillation of the mosaic-covered surfaces as the light skips from facet to facet.Awesome in size and opulent in finish though it was, it is not for these reasons that Hagia Sofia is an architectural feat. It is because of its structural brilliance and the subtlety with which the spaces are articulatedunderlining the difference between the practical directness of Western architecture and the nuances of oriental. Nevertheless, the church remains Roman. The subdivision of its spaces according to their purposes coincides with contemporary Western basilicas: atrium, narthex, nave and aisles, sanctuary, apse, vestries, and altar are all present. There the similarity ends. Western churches were long and narrow, and their slender parallel walls supported timber-framed roofs. The plan of Hagia Sofia is almost square, approximately 250 by 220 feet 75 by 67 meters, and the four massive piers, each about 25 by 60 feet 7.6 by 18.3 meters, carry a domical roof. Yet when the spatial arrangement of the church is considered, it can be readily seen that by the use of elegant screens to separate aisles and nave, and the placing of the apse, the architects skillfully manipulated a vast single space to meet the liturgical program of the clergy. The interior space is made cruciform by projecting a large hemidome over the apse and smaller ones above the aisles. This daring experimentation with space was made possible through the use of the pendentive, a structural device that allowed Byzantine architects to satisfactorily roof a cubical volume with a dome. That had never been achieved in the West, and never before on such a scale in the East, from whose vernacular architecture it had been drawn.Hagia Sofia has undergone many changes in its 1,500-year lifetime, with both natural forces and desecration taking their toll. The church was structurally damaged by earthquake only a year after its dedication, and again in 557 and 559. In 562 it was restored and reinforced by Isidoros, nephew of the original architect, who also raised the dome by about 20 feet 6.25 meters. Further earthquake damage in 869 and 889 closed it for five years. The Iconoclasts vandalized the original mosaics in the eighth and ninth centuries, but most were replaced. Hagia Sofias finest ornaments were plundered by the Fourth Crusade in 1204, and the building was seriously damaged. Large buttresses were added to the north and south facades in 1317, but that did not prevent considerable earthquake damage about thirty years later. Mehmet the Conqueror took Istanbul for Islam in 1453, and Hagia Sofia, although retaining its name, was put to use as a mosque. Large timber medallions with Koranic texts were hung on the walls of the interior and the Christian mosaics whitewashed over. Minarets were added at various times during the Ottoman period. The building became a museum in February 1935. At the end of the twentieth century Hagia Sofia stood on the United Nations World Heritage Watch List, one of the worlds 100 most threatened buildings.Despite

Paris, France
Once described by novelist Emile Zola as theventre de Paris belly of Paris, Les Halles, situated in a square northeast of the Louvre, was the popular and vibrant market quarter. It was alive during the day with merchants and shoppers and at night with vehicles bringing produce from the French provinces and other Mediterranean countries, night butchers preparing meat for the next days business, and inquisitive patrons from nearby restaurants and bars. Originally the market comprised open-air stalls, but between 1853 and 1866 a series of pavilions was built to create a covered market of grand scale. Known as the Halles Centrales and designed by architect Victor Baltard 1805 1874 with Felix-Emmanuel Callet 1791 1854, the project was commissioned by Emperor Napoleon III as part of the mid-nineteenth-century remodeling of Paris planned by Baron Georges-Eugene Haussmann. Influenced by his experience ofmodern life in London, Napoleon III was intent upon establishing Paris as an imperial city capable of exploiting new developments in industry, trade, and transport. He aimed to improve housing conditions, remove slums home to many of the insurgents of the French Revolution of 1789 and nineteenth-century uprisings, establish public parks, and construct grand streets, public buildings, and monuments. The gigantic Halles Centrales was an iron-framed complex that became the prototype for covered market buildings in France and elsewhere, just one of many new structures that emerged during theHaussmannization of Paris. Baltards first design was for a classical building with masonry walls. However, the emperor requested that he use iron instead, as a demonstration of Frances industrial prowess. Pressure from a public wanting a spacious, well-lit, and well-ventilated structure forced the architect to adopt a design not unlike the railroad sheds of the 1830s and 1840s. He planned a series of rectangular pavilions laid out in a grid pattern and connected by broad streets, all but one of which was covered. Initially there were six pavilions, but the number was soon extended to ten a further two were added in 1936. Based on a 19-foot 6-meter module, they measured either 137 by 197 feet or 197 by 197 feet 42 by 54 meters or 54 by 54 meters. At one end of the long axis there was a rotunda, near to which were the administration and public services. A vast basement housed food stores and such facilities as a butter-mixing room and poultry abattoir, Externally the building frame comprised hollow cast-iron columns, which acted as downpipes for rainwater they were connected by arched girders. The interior columns, also of iron, supported clerestory walls that rose above the eaves of the pavilions. All was covered with a glazed roof. The infill walls were usually single-skin brick, with stone dressings at the top and bottom above them were horizontal bands of timber-framed opening windows and fixed louvers. Between 1962 and 1969, the food markets were moved to Rungis, south of Paris. The Halles Centrales site was earmarked for renewal, and while debate raged over how it would be utilized, its former pavilions were home to exhibitions and other cultural events. In the early 1970s ten of the graceful buildings were demolished two others were dismantled and reassembled, one in Nogent-sur-Marne, France, and the other in Yokohama, Japan. Les Halles was replaced by the Forum des Halles, an underground metro station with a regional railroad link 1977 and a multistory shopping center 1979. Popular opposition to the demolition of the Halles Centrales led to a wider movement for the conservation of Frances nineteenth-century industrial heritage.

Iraq
The ancient city of Babylon stood on the east bank of the Euphrates River about 30 miles 50 kilometers south of modern Baghdad. Philo of Byzantium, writing in the third century b.c., listed so-called Hanging Gardens among the seven wonders of the world. Tradition has it that the gardens were built by King Nebuchadnezzar II ruled ca. 605 561 b.c. for his wife Amytis, because she missed the mountainous landscape of her native Media. They may have been commissioned by the half-legendary Queen Sammu-ramut known as Semiramis some 200 years earlier. Contemporary Babylonian clay tablets intriguingly ignore them amid lucid descriptions of Nebuchadnezzars palace and the city and defenses. Neither the Babylonian priest Berossus nor Philo and other Greek writersthe geographer Strabo and the historian Diodorus Siculuswho centuries later described the gardens ever saw them, and no certain traces survive. Some historians suggest they were merely romantic constructs upon accounts of Mesopotamia carried to Greece after the Macedonian conquest in 330 b.c. The German archeologist Robert Koldewey believed he had found the substructure of Nebuchadnezzars gardens around 1899 when he uncovered several unusual vaulted foundation chambers, atypically built of stone, and a well in the northeast corner of the palace. From more recent excavations concentrated on the southern palace, archeologists surmise that they were in another building, hundreds of meters from the river. Because Strabos description had placed them close to the Euphrates, other scholars disagreed. There is another possibility. More recently, the suggestion has been made that the classical writers were confused, and that the gardens were not in Babylon at all, but in the Assyrian city of Sennacherib, Nineveh, which stood on the Tigris 250 miles 400 kilometers to the north. Nineveh was about 1,800 acres 700 hectares in area, enclosed by 10 miles 16 kilometers of 50-foot-high 15-meter walls. Within and outside its defenses, Sennacherib created lush parks and gardens, full of exotic plants and watered from a complex, system of aqueducts and canals. They are described on a clay prism dating from about 690 b.c. So is the way in which the huge volume of water needed for irrigation was raised to the highest terrace to flow to lower levels through sloping channels. The king had great brass archimedean screws cast four centuries before Archimedes! to lift the water from the ample supply. His description matches those of the later writers. For example, Diodorus Siculus portrays a garden supposedly in Babylon, whose approachsloped like a hillside and whose structure rosetier on tier, adding thatwater machines [raised] the water in great abundance from the river, although no one outside could see it. Whether the Hanging Gardens existed or not, or whether they were in Babylon or Nineveh, the descriptions were evocative.

Jerusalem, Israel
Hezekiahs Tunnel, an eighth-century-b.c. subterranean aqueduct in Jerusalem, was a magnificent engineering achievement. Teams of stonecutters, working no more than two abreast and using hand tools, cut the 1,730-foot 576-meter passageway of bedrock, probably in about seven months. Starting from both ends, between 33 and 150 feet 10 and 45 meters underground, without sophisticated surveying instruments or contact with the surface, they were able to reach a meeting point. The Canaanite citadel called Jebus stood on a slope that fell away into a deep valley outside the present-day walls of Jerusalems Old City. It had a defensible water supply upon which the conquering Israelites were to build, reaching a climax in the reign of Hezekiah, King of Judah 727 698 b.c.. Jerusalem depended on a single source of water: the Gihon or Gichon Spring. Fed from underground streams and hidden in a small cave on the citys eastern slope, it also irrigated surrounding farmland through canals built along the Kidron creek bed. Archeologists have found evidence of Canaanite fortifications designed to protect the spring. Gihons name describes its erratic nature: the Hebrew word meanseruption orgushing. Although reliably producing up to 245,000 gallons 1.1 million liters a day, the spring would flow profusely for half an hour, then reduce to a trickle for between four and ten hourslonger intervals in summer, shorter in winter. A response to siege warfare generated the sophisticated water-reticulation systems that culminated in Hezekiahs Tunnel, one of the great engineering achievements of ancient Jerusalem. Possibly as early as 1800 b.c., the Jebusites were able to reach Gihon from within their walls: a diagonal tunnel, like others in the region, followed a natural rock fissure to a point from which pitchers could be lowered to the spring. Some scholars believe that this was the passageway mentioned in the Bible, through which Joab led King Davids men into the city, which they then overthrew. It is known as Warrens Shaft, for Colonel Charles Warren, an Englishman who discovered it in 1867. The debate continues over its date and who built it. The Israelites augmented this basic system in two stages. First, they built the Siloam Shiloah Channel, probably during the peaceful reign of King Solomon 970 928 b.c.. From Gihon a part-open, part-tunneled conduit ran south along the Kidron brook to a reservoir in the HaGal Tyropoeon Valley at the southwestern corner of Jerusalem, which by then had been extended to what are now known as the Jewish and Armenian Quarters. Sluices along its eastern side had stone gates that could be opened to irrigate the gardens and fields in the valley below. Ancient Jerusalems most extraordinary hydraulic engineering projectperhaps better classified as a civil defense undertakingwas Hezekiahs Tunnel, discovered in 1838 by the American scholar Edward Robinson. Under the implacable Sennacherib 705 681 b.c., the Assyrian Empire extended from the Persian Gulf to the Black Sea, and westward to the Nile valley. His father Sargon had overrun the northern kingdom of Israel, and Sennacherib was concerned with consolidating the family conquests. Hezekiah, the charismatic ruler of the relatively puny kingdom of Judah, reassured by the prophet Isaiah that God would protect Jerusalem, stood against the Assyrian might. He stockpiled weapons and extended the citys defenses by building the 23-foot-thick 7-meter Broad Wall. And at the first inkling of invasion he had devised a measure that would help his people survive a siege. He plannedto stop the water of the springs that were outside the city [and] closed the upper outlet of the waters of Gihon and directed them down to the west side of the City of David 2 Chron. 32:30. Hezekiahs Tunnel 701 b.c., still a functioning watercourse almost 3,000 years later, connects the Gihon Spring and the Pool of Siloam or Hezekiahs Pool, specially constructed at the south end of Jerusalem, where the king had extended the outer defenses. Thus the Bible calls the poolthe reservoir between the two walls Isa. 22. The direct distance between spring and reservoir is about 1,100 feet 330 meters, but the winding tunnel is 1,730 feet 576 meters long. On average, it is about 3 feet 900 millimeters wide and varies between 3 and 9 feet in height in places, it is 150 feet 45 meters beneath the surface of the hilly city. The fall from Gihon to Siloam is about 6 feet 1.8 meters, that is, a grade of about 1 in 70. The tunnel was excavated by two groups of workers, starting at each end and cutting toward each other through the rock to eventually connect. The Siloam Tunnel Inscription, engraved on one of the walls and found in 1880, celebrated their meeting: While there were still three cubits to be cut through, [there was heard] the voice of a man calling to his fellow, for there was an overlap in the rock on the right [and on the left]. And when the tunnel was driven through, the quarrymen hewed

The fifth-century-b.c. Greek architect Hippodamos of Miletus has long been known as thefather of city planning. Although the claim has been challenged by some historians, his contribution at least in the West was the notion of ordered city planning, as opposed to the uncontrolled growth of earlier times. For example, fifth-century-b.c. Athens, the dominant Hellenic city, was an undisciplined accretion of houses lining crooked narrow streets and lanes whose routes were determined by the topography around the great Acropolis. Hippodamos has been credited with the introduction of the orthogonal planagridiron with streets at right angles dividing the city into the kinds of blocks we are familiar with. His ideal plan was zoned by land use, with blocks reserved for public buildings and open spaces, integrated with the houses to provide a cohesive social, environment. However, some elements of the Hippodamean city can be found in earlier Greek settlements. For example, the colony of Smyrna, near what is now the Aegean coast of Turkey, was rebuilt in the seventh century b.c. with parallel north-south streets. Therefore, it may have been that Hippodamos simply formalized generally held conventions in his theoretical writings and applied them in the cities he designed. In Politics, Aristotle remarks upon the Miletians long hair and eccentric dress and notes his wide interest in natural philosophy. It was unusual for an architect to discourse upon the best form of government, but that did not prevent Hippodamos from doing so. His theories of physical planning were linked to social planning clearly he saw the planners role not only in terms of functional and esthetic design but also in human organization of religious, civic, and commercial activities. Adopting what today would be called a determinist approach, Hippodamos divided his optimum population of 10,000 into three: artisans, farmers every Greek city had its agricultural hinterland, and military. Then he divided the city into three parts: one for worshiping the gods, one to support the soldiers, and the third private, the property of the common people. He went further, categorizing laws into three sorts: insult, injury, and homicide. The political scientist Daniel J. Mahoney has commented,Hippodamos characteristically divided everythingthe population, laws, and landinto threes because he wrongly thought that human nature was amenable to mathematical manipulation. Yet Hippodamos is not remembered for his utopian social views, but for the physical form of his cities. Several have been attributed to him, including his birthplace, Miletus. The prosperous fortified Aegean port stood on a peninsula at the mouth of the Meander River. Established by the Mycenaeans in the middle of the second millennium b.c., it grew to be one of the largest cities in Anatolia, a commercial center with a population said to have reached 100,000. In 499 b.c. with sister Ionian cities, Miletus rebelled against its Persian occupiers. They responded by razing it. Liberated after the Persians defeat at the naval battle of Mycale 479 b.c., the Miletians rebuilt their city according to Hippodamoss orthogonal plan: a repeated pattern of identical blocks with wide main streets crossed by minor thoroughfares. The commercial and religious buildings occupied multiple blocks, and all was enclosed by a defensive wall. Refounded on the site of an ancient city in the mid-fifth century b.c., the smaller port of Priene, north of Miletus, was set out on a Hippodamean grid. Its plan comprised 84 rectangular 120-by-160-foot 37-by-49-meter blocks, covering 93 acres 37 hectares and descending toward the sea from the base of a 1,000-foot 306-meter cliff on Mount Mycale. The north-south streets were steep, even needing to be stepped in places the east-west streets, approximately following the contours, were easier to negotiate. Provision was made for city growth within the encircling walls. In the event, the population remained at 3,000 and more than half the enclosed area was never developed. Reserves for public spaces were part of Hippodamoss plan, and the agora stood upon a central terrace. Around 450 b.c., Hippodamos was commissioned by Perikles to redesign parts of Piraeus, the port of Athens. It stood less than 6 miles 9.6 kilometers southwest of the city on a peninsula surrounded by the Saronic Gulf. He rebuilt the original fortified Themistoclean port, by then about thirty years old, with a well-defined grid of broad streets defining long rectangular blocks. His plan gave better access to the three harbors, dedicated respectively to grain vessels, general cargo ships, and the navy. The parallel Long Walls, about 600 feet 183 meters apart, were completed in 431 b.c. to protect the supply line between Athens and its port during the Peloponnesian War with Sparta. There are several other attributions. Hippodamos almost certainly had a hand in the foundation of the colony of Thurii in southern Italy around 444 b.c. Very regular orthogonal extensions to the city of Olynthos, in what is now Macedonia, were laid out soon after 432 b.c. But it may be that Olynthos and the much later city of Rhodes 408 b.c. on the Aegean island of the same name were laid out by others who implemented the Hippodamean form. That easily surveyed orthogonal form continued to be influential and was perhaps modified by the Romans in any number of their colonial towns. It was revived in the fifteenth century as one of the theoretical bases of Renaissance urban design. Much later, the planners of cities in the New World employed the grid: Savannah, Philadelphia, Chicago, and New York City are all evidence of that. So is San Francisco, where its imposition on a hilly site, even if it provides locations for exciting movie car chases, underlines its suitability for little but the flattest terrain.

When inscribing the Canal du Centre boat lifts in Belgium on its World Heritage List in 1998, UNESCO commented that theyrepresented the apogee of the application of engineering technology to the construction of canals. That holds true for each example described here. The boat lifts exemplify the seemingly limitless mechanical ingenuity of the Victorian Age. The Industrial Revolution, first in Britain and then in the rest of Europe and North America, saw the necessarily rapid growth of inland transportation networks. Although they were soon augmented and often replaced by railroads, canals were the main arteries of industry and commerce. Differences in water levels along their length and at their junctions with rivers were normally overcome by building locks. In order to save time, creative engineers developed a hydraulic mechanism known as a boat lift, which could replace several conventional locks. Among the most ingenious devices of the machine age, the boat lift continued to be refined into the early twentieth century. The principle was simple: a boat or barge entered a watertight trough that was raised or lowered by filling or emptying a counterbalancing trough. It is likely that the first commercial boat lift was built in 1838 on the Grand Western Canal in the English county of Devon. The canal, first suggested in 1768, was intended to link the Bristol Channel on the west coast and the English Channel on the east. Construction did not begin until 1810 and four years later an 11-mile 17.6-kilometer stretch was completed. Extensions were built, and by 1838 the canal reached as far as Taunton in Somerset. A decade later the Great Western Railway linked Bristol and Exeter, and work on the canal was discontinued. But the boat lift served vessels carrying limestone from Tiverton in Devon. Consisting of a pair of 30-foot-long 9-meter wooden troughs joined by chains, it was capable of raising nearly 10 tons 8.14 tonnes through the 47 feet 14 meters that separated two sections of the canal. The most important English model for others in Europe was the Anderton Barge Lift, built near the English salt-producing town of Northwich between 1872 and 1875. It lifted barges over 50 feet 15 meters between the Weaver Navigation and the Trent and Mersey Canal. Designed by the engineers Edward Williams and Edwin Clarke, the mechanism comprised two sets of connected hydraulic cylinders and pistons, each supporting a 76-by-15-foot 23-by-4.7-meter boat tank. In order to lift a boat, a little water was released from the lower tank as the then heavier counterbalancing tank moved downward, the hydraulic system was activated to raise the lower tank, boat and all. The process was augmented by a steam-powered hydraulic pump. The mechanism lasted for about thirty years, but corrosion problems in the hydraulic system led to the construction of a replacement albeit incorporating several parts of the original structure between 1906 and 1908. The new lift continued to carry commercial traffic until the mid-1960s and recreational boats until 1982. Early among the European clones was the lift at Les Fontinettes on the Neuffossee Canal in northern France. Built in 1888 to raise 340-ton 305-tonne canal boats 43 feet 13 meters from the River Aa to the canal, it replaced no fewer than five eighteenth-century locks, dramatically reducing the time needed to negotiate the network of inland waterways linking Calais and Dunkerque with the industrial center of Lille. It was replaced by a single modern lock in 1967. Proposed in 1879, the 17-mile 27-kilometer Canal du Centre in Belgiums industrial Scheldt-Meuse-Rhiue Delta integrates Europes inland waterways. Because they survive in working condition, four lifts near La Louviere, also based on the Anderton model, are unique among their contemporaries. Each lifts boats through 57 feet 17 meters. The first, with a capacity of 450 tons 407 tonnes, was built around 1889 the remaining 340-ton 305-tonne lifts followed between 1908 and 1917. In 1999, as part of a long-term program to increase the capacity of Belgiums major waterways, a single hydraulic elevator was completed at Strepy-Thieu on a new section of the Canal du Centre. It is capable of moving barges of 1,500 tons 1.370 tonnes deadweight vertically though 243 feet 73 metersthe highest lift in the worldin tanks that weigh almost 9,000 tons 8,150 tonnes. Because of growing industrialization in the late nineteenth century, Germanys River Ruhr needed a transport network for raw materials and manufactured goods. In 1899 the Dortmund-Ems Canal was built to connect North Sea harbors to the Ruhr region. The Rhine-Herne Canal, completed in 1914, linked the Rhine with Rotterdam and Amsterdam. The two artificial waterways are joined by the 45-foot 13.5-meter Henrichenburg boat lift at Waltrop. Constructed between 1894 and 1899 it was replaced in 1958 1962. Another early hydraulic lift system was built in the New World: the Peterborough Lift Lock on the Trent-Severn Canal, connecting Lake Ontario with the upper Great Lakes and the West. Completed in 1904 it consisted of two ship liftseach with a mass of 1,900 tons 1,730 tonnes and rising 49 and 65 feet 14.8 and 19.8 meters, respectivelywithin the 4-mile 6.5-kilometer canal, replacing eight conventional locks.

In the second half of the 1920s the modernist architects of Europe, perceiving an urgent need to reform city planning and especially public housing policies, sought to address the social changes resulting from industrialization. At a 1928 meeting at La Sarraz, Switzerland, architects from Austria, Belgium, France, Germany, Holland, Spain, and Switzerland formed the Congres Internationaux dArchitecture Moderne CIAM, agreeing that rationalization and standardization were the chief ways to solve the housing problems each country then faced. CIAM reconvened in Frankfurt in 1929 to discuss the pragmatic issue of existenzenminimumlow-cost residential units. That unit should replace house in its lexicon is an indicator of pervasive socialist thinking indeed, politics could not be excluded from any debate on urbanism and housing policies. In its Athens Charter, derived in 1933 and published ten years later, CIAM offered modern technology as the generic solution to the urban problems that would be exacerbated by World War II. That is, they called for a new way of building, and that displacement of conventional thinking with a problem-solving approach was an architectural feat in itself. Success is a different matter. It is one thing to theorize, quite another to find real solutions. Designers on both sides of the Atlantic were investigating industrialized construction techniques as a means of making better, affordable housing. As early as 1910 the German architect Walter Gropius advocated the industrial production of interchangeable housing components, and in 1914 Le Corbusiers Domino house system employed a standardized framework. It was perhaps inevitable that many of the resulting products were mechanistic and austere, emphasizing structure and detail at the expense of esthetic considerations. This new, efficient way of making architecture was grasped as an opportunity to realize the house as a machine for living in. The first half of the twentieth century is replete with designs for systems and components, too numerous to include here. Suffice it to identify a few key individuals. The French blacksmith and steel fabricator Jean Prouve 1901 1984 began experiments with prefabricated construction in 1925, in partnership with Aluminium Fran

Peru
The brief but glorious ascendancy of the Inka lasted for about sixty years from a.d. 1476. At that moment their empire, Tahuantinsuyu Land of the Four Quarters, was the largest nation on earth. Ruled from the Andean capital, Qosqo, it covered 2,000 miles 3,200 kilometers north to south and 200 miles 320 kilometers inland. The empires northern quarter, Chinchaysuyu, extended beyond what is now Colombia the southern quarter, Collasuyu, reached as far as central Chile the eastern quarter, Antisuyu, included the eastern Andean foothills in modern Bolivia and Argentina and the western quarter, Guntisuyu, embraced the Pacific coast. A critical means of sustaining Inka power over subject peoples was a system of primary and secondary roads whose total length has been estimated to be 25,000 miles 40,000 kilometers, comparable to the communication infrastructure of the Roman Empire, and achieved without the advantage of the wheel or large draft animals. Quite apart from the variety of the terrain, the Inkan transportation network was a great engineering feat, and the response to that diversitymountains and valleys, snow, deserts, and swampsmakes the accomplishment the more remarkable. Near the coast they were dusty tracks, sometimes built on causeways to keep them free of blown sand or sometimes simply pegged out in swamps they were built on stone viaducts and in high rain- or snowfall regions they were paved with cobbles or flagstones. Steep slopes were negotiated by means of steps, often cut into the living rock. The roads sat within a hierarchy, at the apex of which were the two north-south royal, or Inca, roads linking Qosqo with the four quarters of the empire. One crossed the Cordillera from what is now Colombia to Argentina, and the other followed the coastal plains from northern Peru to northern Chile. They were linked by several crossroads. The rest of the primary network consisted of principal or rich roads and big or broad roads, covering a conservatively estimated 15,000 miles 25,000 kilometers. A secondary system of peoples roads joined villages and districts throughout the Tahuantinsuyu, bringing the total length of roads to some 25,000 miles 40,000 kilometers. Inevitably, in mountainous country, bridges of various construction were necessary. These ranged from simple stone slabs, through small log bridges and flying foxes, to rope-and-leather suspension bridges, some spanning chasms up to 500 feet 150 meters wide. There were even floating bridges made of rope and reeds. A corollary of the Incan road system was the army of young athletes called chaqsi, who ran in relays between staging posts chasqwasi set at 8- to 15-mile 13- to 24-kilometer intervals. They carried verbal messages and sometimes goods. For example, the royal court at Qosqo enjoyed fresh fish delivered from the coast over 200 miles 320 kilometers away. The messenger service was continuous, relays of runners covering up to 300 miles 480 kilometers a day. Armies were deployed along the roads, officials moved between administrative centers, priests traveled to supervise religious services, pilgrims wound their way to shrines, merchants transported their goods by llama or alpaca caravans, and herders coaxed flocks down from the high country. For these more leisurely travelers, services were provided at large villages called tanpu along the major routes, strategically located at intervals representing one days walk, say 25 to 30 miles 40 to 50 kilometers. In the tanpu, lodging, food, and clothing were available for thousands of people at once, because for political or economic reasons, the Inka sometimes would relocate entire populations. These administrative and service centers were as important to the Inkas as the roads themselves from them, imperial bureaucrats exercised control over the empire. Thus, for example, several centers were established on the royal road at Tambo Colorado and Huanuco Viejo, each with more than 3,000 buildings to house the civil service, manufacturing and warehouse functions, catering for local food shortages, and so on. Smaller settlements were sometimes built at half-day intervals. At the beginning of the twenty-first century some 14,000 miles 22,000 kilometers of Inka roads remain discernible, but much of the continuity has gone, destroyed by modern highways, radio masts, or hydroelectric power stations. Tourism also is taking its toll. Progress is inevitable, but measures are being taken to preserve remnants of the Inka Trail. For example, in the 1990s the Machu Picchu Historical Sanctuary commissioned the British company Mountain Path Repair International to produce a sustainable management plan for the road between Qosqo and the spectacular site and to restore the eroded sections