World's longest, deepest train tunnel opens in Switzerland

The world's longest and deepest train tunnel has opened in Switzerland, nearly two decades after construction began. Stretching for 35 miles under the Swiss Alps, the Gotthard Base Tunnel will connect the cities of Bodio and Erstfeld, as part of an ambitious high-speed rail line that will eventually stretch from Rotterdam in the Netherlands to the Italian city of Genoa. The tunnel is longer than both the 33-mile Seikan rail tunnel in Japan and the 31-mile Channel Tunnel, which connects France and the UK, and reaches depths of up to 1.4 miles below the surface of the mountains.

Several European heads of state were in attendance for the tunnel's inauguration on Wednesday, The New York Times reports, and 500 people were selected from a lottery to participate in its first train ride. In a speech at the northern end of the tunnel, Swiss Federal President Johann Schneider-Ammann described the inauguration as a "giant step for Switzerland but equally for our neighbors and the rest of the continent."

Proposals for the base tunnel date back to 1947, but the project wasn't approved until 1992, following a voter referendum. Over the course of 17 years, workers excavated more than 28 million tons of rock from the site, which they repurposed as concrete for the tunnel. Full service is expected to begin in December, with passenger trains traveling at a maximum speed of 155 miles per hour. When service begins, the travel time between Zurich and Milan will be reduced by an hour.

The completion of the $12.2 billion project was marked with an extravagant ceremony this week, though the tunnel may soon be surpassed by an even more ambitious project. China has announced plans to build an underwater train tunnel that if completed, would be 76 miles long.