The Channel Tunnel is an undersea railway tunnel which connects the UK and France via Kent and Calais, beneath the English Channel. Having opened in 1994, it has the longest underwater section of ...

If asked which underwater tunnel in the world was longest, you'd be pardoned for proposing the Channel Tunnel, located between the UK and France, which is an admirable 31 miles long. But ...

The hypothetical tunnel between the U.S. and the UK has been branded as a "high-risk" project by one of the world's leading megaprojects economists.

The Seikan in Japan is an “awe-inspiring” underwater tunnel that runs for 33.46 miles. There's also the Channel Tunnel that connects UK and France - which is also long at 31.4 miles.