After almost two decades of construction, the Gotthard Base Tunnel officially opened in June 2016, but regular rail service didn't begin running through the passage until December of that year. The tunnel, which at points travels as deep as 1.4 miles beneath the surface, took the title of longest and deepest rail line in the world from the previous record holder, Japan's Seikan Tunnel, which measures 33.5 miles long. The tunnel was built below the Swiss Alps in order to connect the southern and northern parts of Europe.
On December 11, 2016, the 35-mile Gotthard Base Tunnel (GBT) — the longest tunnel in the world — began full rail service, allowing passengers to ride underneath the Swiss Alps for a trip from Zurich to Lugano, Switzerland, on the Italian border. The tunnel was under construction for 17 years, and has cut down the previous travel time for the same trip by 30 minutes.