Citylab from The Atlantic » Switzerland is opening the world’s longest rail tunnel on June 1, 2016. The Gotthard Base Tunnel is 35.5 miles long and connects Switzerland with Northern Italy running up to 150 miles per hour, and sometimes 8,000 feet below mountain peaks. The project cost to date is $10.3 billion, and tunnel drilling took place from 1996 to 2011. This tunnel is the longest of several planned for connection throughout Europe.