Record: 57 km
The Gotthard Base Tunnel (GBT) (German: Gotthard-Basistunnel; French: Tunnel de base du Saint-Gothard; Italian: Galleria di base del San Gottardo; Romansh: Tunnel da basa dal Son Gottard) is a railway base tunnel through the Alps in Switzerland, which opened on 1 June 2016 with full service to begin in December 2016. With a route length of 57.09 km (35.5 mi) and a total of 151.84 km (94.3 mi) of tunnels, shafts and passages, it is the world's longest and deepest traffic tunnel and the first flat, low-level route through the Alps.Website:http://www.gottardo2016.ch/en