Hi everybady, Tunnel is a useful alternative way to help and facilitate transportation from one place to another. Various models of tunnels are made, from those that penetrate the land surface to mountains and through the seabed. Uniquely, there is one tunnel that managed to penetrate under the sea.

One of them is in Japan and is the first in the world, the Saiken Tunnel. The Saiken Tunnel passes under the Tsugaru Strait which connects Honshu Island and Hokkaido Island. With a length of 53.85 kilometers, until now Saiken was asked to be the world's longest underwater tunnel. Besides Seikan, it turns out that there are other longest underwater/water tunnels in the world including:
Qingdao Jiaozhou Bay . Tunnel
North Cape Tunnel
Marmaray Tunnel
Holland Tunnel
Severn Tunnel
Channel Tunnel