How Denmark's World's Longest Immersed Tunnel Waited Two Years for One Machine

73,500 tonnes per standard element, sunk into a trench in the Baltic seabed: the Fehmarnbelt tunnel is cast on land, then lowered into the sea, one piece at a time. The 18 km route crosses Ice Age clay till, soft muds and swelling Paleogene clay. Crews dredged about 15 million m³, then built a factory that casts each 217 m element in nine segments. Two purpose-built pontoons, IVY 1 and IVY 2, lower them on 66 winches. By the numbers: 89 elements in all; a design target of 15 mm placement precision; the first immersion took about 14 hours, in May 2026. The cost: Denmark's construction law set DKK 55.1 billion in 2015 prices (about €7.4B). Sund & Bælt says the delay will raise that, with no new figure yet; tolls and rail charges are meant to repay its state-guaranteed loans. Chapters: 0:00 A Tunnel That Goes to Sea 0:35 The Night the First Box Sailed 3:06 Ice Age Seabed, 18 km Trench 6:04 The Tunnel Factory 9:06 Inside a 73,500-Tonne Box 12:12 Two Years Waiting for IVY 14:40 Two Portals, a New Opening Date 16:08 The Cost and Who Pays 18:50 The First Immersion 20:44 85 Elements to Go If you know San Francisco's BART Transbay Tube, the Channel Tunnel or the Øresund link, this is the next step: Arup says this tunnel will be more than three times longer than the Transbay Tube. Mega Engineering: how the world's hardest structures are built, tested and sometimes nearly lost, every number sourced. Sources: Femern A/S and Sund & Bælt; Germany's Federal Administrative Court; German transport ministry; ENR; Ingeniøren; Arup; Transportation Research Part A. This video is an educational documentary produced with AI-assisted narration and visuals. Visuals are illustrative reconstructions, not footage of the actual site. All figures are sourced from publicly available engineering and government records; where sources disagree, the range is stated. This video does not take a position on any political or legal dispute connected to this project. #Construction #Engineering #MegaProjects #CivilEngineering #Infrastructure #Tunnel #Fehmarnbelt #Denmark DISCLAIMER ____________________________________ This is not engineering advice. Everything here is for informational and entertainment purposes only. Contact an engineer licensed to practice in your area if you need professional advice or services. All non-licensed clips used for fair use commentary, criticism, and educational purposes.