Tongyeong Undersea Tunnel

Tongyeong Undersea Tunnel is an undersea tunnel in Republic of Korea, linking Goseong peninsular ward of Tongyeong to the Mireukdo island. It measures 5 m wide by 3.5 m high and is 483 m long, running at a depth of 13.5 m below the sea surface measured at high tide. Completed in 1932, it is the first undersea tunnel built in Asia.