The first tunnel under a navigable river, symbolizing pioneering engineering from 1825–1843.
World's oldest underwater rail tunnel, establishing a critical Mersey crossing since 1886.
World's longest tunnel with an undersea segment, a marvel of modern engineering since 1988.
Longest undersea portion railway tunnel, connecting two nations since 1994.
Innovative road tunnel linking Asia and Europe under the Bosphorus Strait since 2016.
Combines bridge and tunnel, slashing travel time across Tokyo Bay since 1997.
India's first underwater metro, a quick passage under the Hooghly River since 2021.
55 km-long sea crossing with a significant tunnel section, connecting three regions since 2018.