The Siberia-Alaska tunnel is easily one of the most impressive engineering projects to ever be attempted. The project, recently given the green light by Russian authorities, proposes an underground tunnel connecting Russia to Alaska via rail.
The last time Russia and Alaska were physically connected by anything was thousands of years ago when the Bering Strait was covered in ice. The new project would connect America and Russia via an underground train tunnel for the purpose of moving freight. The tunnel would be twice as long as the Chunnel connecting England and France and cost $65 billion to build, with the funds coming from both the public and private sector. There are currently no plans to use the tunnel to transport passengers, but you never know what could happen. The Siberia-Alaska tunnel will be an exciting project to follow and could go down as one of the greatest feats of engineering ever.