The world’s longest tunnel, the Gotthard Base Tunnel in Switzerland, is 57 km long. It runs under the Alps, with trains speeding through at 250 km/h. Construction took 17 years and cost $12 billion!
The world’s longest tunnel, the Gotthard Base Tunnel in Switzerland, is 57 km long. It runs under the Alps, with trains speeding through at 250 km/h. Construction took 17 years and cost $12 billion!