March 13, 1988The Seikan Tunnel, the longest undersea tunnel in the world, opens between Aomori and Hakodate, Japan.
The Seikan Tunnel is a 53.85-kilometre (33.46 mi) railway tunnel in Japan, with a 23.3-kilometre (14.5 mi) long portion under the seabed. Track level is about 140 metres (460 ft) below seabed and 240 m (790 ft) below sea level. It travels beneath the Tsugaru Strait—connecting Aomori Prefecture on the Japanese island of Honshu and the island of Hokkaido—as part of the Kaikyo Line of Hokkaido Railway Company. The name Seikan comes from combining the on'yomi readings of the first characters of Aomori and Hakodate, the nearest major city on the Hokkaido side.