Inside the Gotthard Base Tunnel. (Photo: Hannes Ortlieb/CC BY-SA 3.0)

In a little more than a week, the longest and deepest tunnel of its kind will open to trains.

The Gotthard Base Tunnel, in southern Switzerland, cuts through 35.5 miles of the Swiss Alps, and, after 17 years, $12 billion, eight deaths, and 31 million tons of displaced rock, is set to open on June 1, according to NBC News

The tunnel will not begin carrying passengers until December, however, after a period of testing. But when it’s fully operational, according to NBC News, it will cut travel time from Zurich to Milan nearly in a half, from over four hours to around 2.5 hours. 

That’s in part because the tunnel will have 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 will be a little over four miles longer than the famous Channel Tunnel, or Chunnel, which connects France and England. 

And like the Chunnel, the Gotthard Base Tunnel comprises two tunnels for trains, one for each direction. The amount of rock displaced in building the new tunnel through the Alps was enough to build five Egyptian Giza pyramids. 

“The communities at either end have been living with the construction for a whole generation so this is an exciting moment for them, too,” Claire Smith, an engineer and editor, told NBC News. “It’s been a big part of their lives for a long time.”