Seikan Tunnel
The Seikan Tunnel（Ja:青函トンネル）is a railway tunnel in Japan. It connects Hokkaido to Aomori Prefecture. This tunnel is the second longest transport tunnel in the world. The tunnel is 53.85 km (33.49 miles) long. 23.3 km (14.5 mile) of the tunnel is underwater.  There are two stations in the tunnel.