[The World's 20 Most Amazing Tunnels]Gotthard Base Tunnel, Switzerland

 

 

 

When it opens for service in 2016, the more than 35-mile-long Gotthard Base Tunnel deep underneath the peaks of the Swiss Alps will become the longest railroad tunnel in the world, besting Japan's Seikan Tunnel and Norway's Laerdal Tunnel by many miles each. (Sebastien Bozon/AFP/Getty Images)