A monumental engineering project beneath the Baltic Sea is set to forge a new, rapid link between two European nations. The Fehmarn Belt Fixed Link, an immersed tunnel, is on course to become the world's longest immersed tunnel and rail link upon its scheduled completion in 2029.
A Colossal Undersea Connection
Stretching an impressive 18 kilometres (11 miles), the tunnel will directly connect the Danish island of Lolland with Germany's Fehmarn island. Described by its developer, Femern, as Denmark's largest-ever infrastructure project, the fixed link promises to dramatically reshape travel and trade routes between Scandinavia and mainland Europe.
The project carries a staggering estimated cost of DKK 55.1 billion (£6.4 billion). The European Union is contributing significant funding, having granted approximately €1.3 billion (£1.1 billion) towards the construction. The chosen method is an immersed tunnel, a technique Femern states is a "safe, tested and efficient way of building an underwater tunnel", developed in Denmark and building on experience from projects like the Øresund Tunnel.
Engineering on a Gigantic Scale
The Institution of Civil Engineers has hailed the endeavour as a "remarkable engineering feat". Unlike bored tunnels, this immersed tunnel will be constructed from 89 massive concrete elements, each weighing a colossal 73,500 tonnes. These segments are constructed on land, fitted with waterproof bulkheads, and then carefully towed into position on the seabed by tugboats.
The process has been likened to assembling giant Lego pieces, with the 89 elements being connected sequentially to form the complete, continuous structure. Once in place, the tunnel will sit atop the seabed, posing no obstacle to vessel traffic in the busy Fehmarnbelt waterway.
Safety and Future Impact
Safety has been a paramount concern in the design. The tunnel will be equipped with continuous hard shoulders and emergency exits along its entire length. Developers assert that journeying through the Fehmarnbelt tunnel will be just as safe as travelling on a corresponding section of motorway above ground.
The primary impact of this mega-project will be a drastic reduction in journey times. By providing a fixed, high-capacity rail and road link, it will bypass the need for ferry crossings, boosting connectivity, trade, and tourism between Central Europe and the Nordic region. Its completion in 2029 will mark a new chapter in European transport infrastructure.
