Denmark and Germany will soon be linked by an 18-kilometre-long underwater tunnel. The Fehmarnbelt Tunnel will be the longest combined rail and road tunnel anywhere in the world when it is completed in 2029.
This €10 billion project - which crosses a stretch of the Baltic Sea known as the Fehmarn Belt - will connect Rødbyhavn on the Danish island of Lolland and Puttgarden in Germany.
The tunnel will have two double-lane motorways and two electrified rail tracks. The journey through it will take seven minutes by train and 10 minutes by car, avoiding a 160 kilometre detour across the Danish mainland. Rail travel times from Hamburg in Germany to Copenhagen in Demark will be cut from around five hours to less than three.
A road link will replace an incredibly busy ferry service that carries millions of passengers a year, slashing travel times by almost an hour.
Denmark is also planning to build high-speed electric rail lines to and from the tunnel. And train services will continue on past the Danish border to Sweden, Norway and Finland.