Gotthard Base Tunnel

Railway tunnel through the Swiss Alps

The Gotthard Base Tunnel (GBT; German: Gotthard-Basistunnel, Italian: Galleria di base del San Gottardo, Romansh: Tunnel da basa dal Sogn Gottard) is a railway tunnel through the Alps in Switzerland. It opened in June 2016 and full service began the following December. With a route length of 57.09 km (35.47 mi), it is the world's longest railway and deepest traffic tunnel and the first flat, low-level route through the Alps.

From Wikipedia, under CC BY-SA. More on occurri.