The Fehmarnbelt Tunnel Will Surpass The Øresund Tunnel As The World’s Longest Immersed Tunnel. Spanning 18 km And 40m BSL Under The Baltic Sea, It Connects Germany And Denmark Using Precast Segments Instead Of Tunnel Boring Machines. Completing In 2029 At ~$7 Billion, It Will Reduce Travel Times, Boost Trade, & Showcase Environmental Care.
The World’s Longest Immersed Tunnel Is Almost Built—a $7 Billion Project Without a Tunnel Boring MachineWhat if the future of tunnels wasn’t about digging? The Fehmarnbelt Tunnel, the world’s largest immersed tunnel, is being built without a single tunnel boring machine. Instead, engineers are using a bold, unconventional method that’s faster, more precise, and environmentally conscious. Stretching 18 kilometers beneath the Baltic Sea, this $7 billion project is set to transform travel and trade in Europe.