At long last, after almost two decades of waiting, the Gotthard Base Tunnel is open for the public's use. Here are the things that you should know about this tunnel.

It is the world's deepest and longest rail tunnel. Gotthard Base Tunnel is 57.5 kilometers long. It surpassed the Seikan Tunnel in Japan, which is 53.9 kilometers long, and Eurotunel in the UK, which is 50.5 kilometers long. The Swiss federal railway service said it is expected to accommodate 15,000 daily rail passengers, from current 9,000 people using the old route.

The tunnel took 17 years to make. This means 43,800 non-stop hours of work by 125 workers following three rotations of shifts. The plan however has been conceptualized in 1947 by Swiss engineer Carl Eduard Grunner. The push for construction started in 1999.

It will increase capacity of travel to 260 freight trains daily. This is almost double the original capacity of the old line at 180 freight trains daily. The route will also cut the course between Bellinzona and Altdorf by 30 kilometers. Passenger freight trains will leave every 30 minutes.

It costs USD$12.3 billion to make. In Swiss currency, Gotthard Base Tunnel costs around 12.2 billion francs. If you add the Lötschberg and Ceneri tunnels, the Swiss government spent around about USD$23 billion for railway tunnels. For the opening events in June, the government spent USD$12 million.

It caught the attention of prominent people. 1,100 people tested the tunnel on June 1, including French President Francois Hollande, German Chancellor Angela Merkel, and Italian Prime Minister Matteo Renzi. Some of the first time Swiss riders are selected through a raffle draw. Swiss president Johann Schneider-Amman hopes that the tunnel would unite the residents and economies of Europe.

It will be open to the public on Dec. 11, 2016. The Swiss federal railway company is planning on testing the tunnel for six months to ensure safety. If you have missed the special preview trips on June 4 and 5, you can experience the trip virtually through a 360-degree video released by broadcasting company SRF.