The Fehmarnbelt Tunnel, currently under construction, is set to become the world’s longest immersed tunnel, connecting Rødbyhavn in Denmark with Puttgarden in Germany. Spanning 18 kilometers (approximately 11 miles), it will consist of a four-lane motorway and a double-track railway, significantly reducing travel time between the two countries. What once took 45 minutes by ferry will soon take just seven minutes by train and ten minutes by car. This ambitious infrastructure project marks a transformative step in Scandinavian and European transportation networks.

Construction began in 2020 and is expected to be completed by 2029, with extensive dredging and land reclamation already underway. The tunnel will be built from pre-fabricated hollow concrete elements, each weighing 73,000 tons and produced at a custom-built factory near Rødbyhavn. These elements will be submerged into a trench on the seabed and sealed together to form a watertight passage. The process involves precision engineering and coordination on an unprecedented scale, with strict environmental and safety standards.

Funded primarily by Denmark at a cost of around €7.1 billion, the project is being executed by Femern A/S, a subsidiary of the Danish state-owned Sund & Bælt Holding. Though Germany is not contributing financially, it has played a key role in granting approvals and preparing the connecting rail infrastructure on its side. The tunnel is part of the Trans-European Transport Network (TEN-T), designed to improve connectivity and economic integration across Europe.

Beyond improving transport links, the Fehmarnbelt Tunnel is expected to bring substantial economic benefits, including increased trade, tourism, and job creation. It will enhance connections between Scandinavia and Central Europe, reduce carbon emissions by shifting traffic from air and ferry to rail, and promote greener, faster travel. The tunnel stands as a symbol of engineering innovation and international cooperation.