The world's longest rail tunnel has been officially opened in Switzerland, after 17 years of construction.
The Gotthard Base Tunnel is 57.1 km (35.3 miles) long, and has been designed to last a century.
It is part of a 23 billion Swiss franc infrastructure project to speed passenger and cargo by rail under the mountain chain that divides Europe's north and south.
The tunnel beats Japan's Seikan Tunnel (53.8km) as the world's longest
It took 17 years to build.
The tunnel is 2.3km below the surface - the altitude of Europe's highest ski resort Val Thorens
The Gotthard Base Tunnel eclipses Japan's 33.4-mile (53.8km) Seikan Tunnel as the world's longest, and burrows deeper - 1.4 miles (2.3km) - than any other rail tunnel.
Engineers had to dig and blast through 73 kinds of rock as hard as granite and as soft as sugar.
Take a ride on board through the world's longest tunnel
The project that federal transport office director Peter Fueglistaler called "a masterpiece of timing, cost and policy" came in on schedule and on budget.
Around 260 freight trains and 65 passenger trains will travel through the two-tube tunnel daily once testing ends later this year.
High-speed trains will whisk passengers in 17 minutes through a passage that took days until the first Alpine rail tunnel opened in 1882.
The tunnel along Europe's main rail line that connects the ports of Rotterdam in the north to Genoa in the south snakes through the mountains as much as 2.3 km below the surface and through rock as hot as 46 degrees Celsius