Seikan Tunnel Seikan Tonneru

Japan
After two decades of planning and construction, the 33.5-mile-long (53.85-kilometer) Seikan submarine tunnel was opened to traffic on 13 March 1988. Part of a railroad between Aomori City and Hakodate City, it links Honshu, the main Japanese island, with Hokkaido to the north, passing under the 459-foot-deep (140-meter) Tsugaru Strait. The tunnel runs 328 feet (100 meters) beneath the ocean bed for 14.5 miles (23.35 kilometers); thus, at 787 feet (240 meters) below sea level, it is the deepest railroad line in the world. The journey between the terminals takes two and a half hours. It has been called one of the most formidable engineering feats of the twentieth century.