The Gotthard Base Tunnel, in southern Switzerland, cuts through 35.5 miles of the Swiss Alps. It is the world’s longest and deepest train tunnel, 8,000 feet deep at its max.
The tunnel opened in 2016 after 17 years and 31 million tons of displaced rock—enough to build five Egyptian Giza pyramids.
The tunnel promises to cut travel time from Zurich to Milan nearly in a half, in part because it has fewer ups and downs, meaning it will be flatter than current routes, allowing for trains to travel faster—to speeds of up to 155 mph.
The tunnel is a little over four miles longer than the famous Channel Tunnel, or Chunnel, which connects France and England. Like the Chunnel, the Gotthard Base Tunnel comprises two tunnels for trains, one for each direction.