Giant Underwater Tunnels That Challenge Engineering: The 5 Most Incredible Constructions That Link Countries, Cross Seas, and Connect Islands

Written by Romário Pereira de Carvalho

Published on 25/07/2025 at 21:06

Updated on 25/07/2025 at 21:25

Imagem por Tambo, via Wikimedia Commons – Licença CC BY-SA 3.0

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Underwater Tunnels Are Transforming Global Transportation With Giant Infrastructure That Crosses Seas, Connects Islands, and Challenges The Limits Of Modern Engineering

Underground Works that cross oceans, bays, and straits are changing transportation in various parts of the planet. Underwater tunnels have shortened distances, facilitated movement, and demonstrated the power of engineering to overcome natural barriers.

In Japan, there is the longest underwater railway tunnel in the world: the Seikan Tunnel. It is 53.85 km long and connects Honshu to Hokkaido.

The project emerged after a maritime accident in 1954 and is now essential for cargo transportation in the country.

ARTICLE CONTINUES BELOW

Main Underwater Tunnels In The World

Seikan Tunnel (Japan) — The longest underwater railway tunnel in the world, measuring 53.85 km.

The Largest Underwater Tunnels In The World — Image: Bmazerolles / Wikimedia Commons

Channel Tunnel (United Kingdom–France) — Connects England and France with a length of 50.49 km.

Tokyo Bay Aqua-Line (Japan) — Combines tunnel and bridge in a 23.7 km route.

Ryfast Tunnel (Norway) — The deepest underwater road tunnel in the world (292 m below sea level).

Eysturoyartunnilin (Faroe Islands) — Tunnel with the only underwater roundabout in the world.

With information from Revista Fórum.

Giant Underwater Tunnels That Challenge Engineering: The 5 Most Incredible Constructions That Link Countries, Cross Seas, and Connect Islands

Underwater Tunnels Are Transforming Global Transportation With Giant Infrastructure That Crosses Seas, Connects Islands, and Challenges The Limits Of Modern Engineering

Main Underwater Tunnels In The World

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Giant Underwater Tunnels That Challenge Engineering: The 5 Most Incredible Constructions That Link Countries, Cross Seas, and Connect Islands

Underwater Tunnels Are Transforming Global Transportation With Giant Infrastructure That Crosses Seas, Connects Islands, and Challenges The Limits Of Modern Engineering

Main Underwater Tunnels In The World

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With a diameter of 15.08 meters, a length of 182 meters, and weighing 3900 tons, the world’s largest tunnel boring machine for drilling super hard rock made a 9 km tunnel in Georgia and impresses with its excavation power.

Material once seen as a poor man’s choice returns as a climate bet, with red clay replacing part of the gray concrete in modern buildings, hospitals, houses, and a cultural center that transforms tradition into a solution against urban heat.

Study solves great ancient mystery: remains of Philip II, father of Alexander the Great, are identified in Vergina and resolves the enigma of the Macedonian royal tombs that had lasted half a century.

Larger than the Toyota Hilux and with a towing capacity of 3.5 tons, the new MG U9 2026 features a 2.5 turbodiesel engine, 520 Nm, 4×4 traction with three locks, and an almost full-size build.

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