How Europe Sinks Tunnel Pieces Heavier Than the Titanic

Under the Baltic Sea, between Denmark and Germany, Europe is building an 18-kilometre tunnel out of 89 giant concrete pieces. Each one is made in a factory on land, floated out to sea like a ship and then sunk on purpose into a trench in the seabed. How do you lower 73,000 tonnes of concrete to exactly the right spot? Why is the tunnel years late? And why might it open with cars, but no trains? Chapters 0:00 A concrete piece that floats 0:45 Why a tunnel here 1:58 01 · The Factory 4:09 02 · The Sinking 5:47 03 · The Delay 6:56 04 · The Other Shore 8:20 Crossing the sea like nothing at all Note: the Fehmarnbelt tunnel is the longest immersed tunnel (built from sunken pieces) ever made; longer undersea tunnels, like the Channel Tunnel, were bored. Piece weights are reported between 73,000 and 73,500 tonnes. The 2032 opening is a Danish press estimate (Børsen); there is no official date. The cost rise to more than DKK 70 billion (about $10.5 billion) is a Børsen estimate; the original budget was DKK 52.6 billion in 2015 prices (about $7.9 billion). Dollar figures at about DKK 6.68 and €0.89 per US$ (ECB rates, 23 Oct 2026); older budgets were converted at today's rate. Diagrams and maps are schematic, not to scale. Main sources Femern A/S — press releases on the first to fourth immersions (May–Sep 2026) and "The Fehmarnbelt tunnel will open in two stages" (17 May 2026) Sund & Bælt — Finance of the Fehmarnbelt link (construction budget) German Federal Ministry of Transport (BMV) — rail connection timetable update (2 Oct 2025) and Fehmarnbelt project page New Civil Engineer (29 Jan 2026) — IVY delays and the 18-month setback Ground Engineering (2 Jun 2026) — opening plans and travel times Fehmarn Business, Børsen and Dagens Byggeri (May–Jun 2026) — new opening estimate and cost heise online (9 Oct 2026), nd/dpa (4 Jun 2026) and NDR — Fehmarnsund tunnel cost and the 2035 date Image credits (Wikimedia Commons) Johan Wessman / News Øresund (CC BY 2.0) · iPierre (CC BY-SA 4.0) · Fabian Horst (CC BY 4.0) · Vmenkov (CC BY-SA 3.0) · DXR (CC BY-SA 4.0) · F.G.O. Stuart, 1912 (public domain) Map data: Natural Earth (public domain) Video footage: Femern A/S (Sund & Bælt) official channel · Indiavision · Pexels Document shown: Femern A/S press release (17 May 2026) Music (Pixabay): "Investigative Ambient Pulse" (nxtlvl) · "Caves of Dawn" and "Sacred Garden" (Guilherme Bernardes) · "Echoes of Destiny" (CSCProd) · "Dark Night" (Valddos) Textures, props and sound effects: Pixabay and our own Thumbnail: AI-generated illustration based on real photos of the tunnel elements and the IVY pontoons. #Fehmarnbelt #Megaprojects #Documentary