The Bering Strait tunnel would connect Russia and Alaska, creating a high-speed rail line, freight route, and a crucial oil pipeline. Twice as long as the channel tunnel, it would be the most ambitious and expensive tunneling project ever attempted. To build it, massive Tunnel Boring Machines would start on both sides of the strait -- 64 miles apart -- and meet in the middle. On either side, workers would lay almost 4,000 miles of railway to connect the nearest rail heads to the tunnel. All this would have to be built in some of the most difficult conditions anywhere on the planet: permafrost regions, mountains and summer swamps, and an entire region known for frequent large magnitude earthquakes that put everything, and everyone, at constant risk.