An unprecedented feat of engineering will be unveiled to the world on June 1, 2016: the Gotthard Base railway tunnel. Here are some facts about the record-breaking achievement:

The tunnel in figures

At 57,1 kilometres long, the Gotthard Base Tunnel is the longest train tunnel in the world.

By comparison, the English Channel train tunnel is 50.5 km long, and the previous record-holder, Japan’s Seikan tunnel is 53.8 km long.

The total cost reached 10.9 billions euros, entirely paid for by Switzerland. It is the same as the budget of the 2012 London Olympics.

The construction works lasted 17 years during which work continued non-stop, with workers doing eight hours shifts.

Over 2,600 workers were involved in the construction; nine of them were killed on site.

To dig the tunnel, workers excavated 13.3 million cubic metres of rubble, five times the volume of the Great Pyramid of Giza.

The first Gotthard Railway tunnel, built between 1872 and 1882 is 15 kilometres long. Its construction killed 177 workers and left 700 injured.

At its lowest point, the tunnel is up to 2,300 metres under the surface.

Passengers trains will run under the mountains at up to 250 km/h and freight trains will reach 160km/h.

The 50 planned passenger trains going through the tunnel each day will thus take on average 20 minutes to go from one end of the tunnel to the other.

It takes a car 1 hour to drive the 79 kilometres of mountain road separating Erstfeld and Biasca, the two ends of the tunnel.

Thanks to the tunnel, a Berlin-Milan train trip will be reduced by 1 hours and 58 minutes.

An international inauguration

French president François Hollande, German Chancellor Angela Merkel and Italian Prime minister Matteo Renzi will attend the inauguration on June 1 with Swiss president Johann Schneider-Ammann. They will take a test train ride together.

The inauguration will also see the tunnel blessed by a Catholic priest, a Protestant minister, a Rabbi and an Imam. To stay neutral – the tunnel is in Switzerland after all – a representative for atheists and non-believers will be there as well.

Over 100,000 visitors are expected for the inauguration party on June 4/5, where they will be entertained by 600 artists.

A 360° tour of the tunnel and the site

The French-speaking Swiss public television has published a spectacular 360° video presenting the building site, the tunnel, the surrounding Saint-Gotthard mountains and the history behind the Gotthard Base Tunnel.