After 17 years of construction the 57-kilometer (35-mile) Gotthard Base Tunnel officially opened six months ago in a colorful ceremony attended by German Chancellor Angela Merkel, French President Francois Hollande and Italian Prime Minister Matteo Renzi.
After thousands of test runs the EC11 express train to Lugano was the first regular passenger train to depart with fare paying passengers.
The Gotthard Base Tunnel breaks several records - it not only the longest, but also the deepest tunnel in the world, passing 2.3 kilometers (1.5 miles) bellow a mountain peak. The depth is comparable to some of the deepest mines on Earth and temperatures can reach 46 degrees Celsius (115 Fahrenheit).
During 17 years of construction, workers had to move over 28 million tons of rock from the inside of the mountain. It was completed about a year ahead of schedule, on a budget 12.2 billion Swiss francs ($12.2 billion, 11.0 billion euro).
The project received financial and engineering support from around the European Union, as the tunnel cutting through the Swiss Alps gives a major boost to trains traveling across Europe. It is also praised for its environmental impact - the improved railway line should get 600,000 trucks off the road every year, with goods loaded onto freight trains instead.
