When it opens in 2029, the Fehmarnbelt Tunnel, the world’s longest immersed tunnel, will link Denmark and Germany, by descending up to 40 meters beneath the Baltic Sea. Femern A/S, the state-owned Danish company in charge of the project and construction started in 2020: the tunnel will be 18 km long, and is one of Europe’s largest infrastructure projects, with a construction budget of over 7 billion euros. It will be built across the Fehmarn Belt, a strait between the island of Fehmarn (Germany) and the island of Lolland (Denmark) as an alternative to the current ferry service from Rødby and Puttgarden: it carries millions of passengers every year and it now takes 45 minutes, but it will take just 7 minutes by train and 10 minutes by car. Read more on CNN