RIVANSHI RAKHRAI
The Thames Tunnel stands as one of the earliest underwater rail tunnels, spanning the Thames River in London.
Hong Kong's Mass Transit Railway (MTR) boasts four underwater railway tunnels that navigate beneath Victoria Harbour.
Stretching 13.5 kilometers beneath the sea, the Marmaray Tunnel in Istanbul links the city's Asian and European sectors.
Japan's Seikan Tunnel, measuring 53.85 kilometers, includes a 23.3-kilometer segment beneath the seabed of the Tsugaru Strait, operating with dual gauges.
Connecting San Francisco and Oakland in California, the Transbay Tube serves as an underwater rail conduit
The Channel Tunnel, traversing beneath the English Channel, seamlessly joins southern England with northern France
In Chittagong, Bangladesh, the Bangabandhu Sheikh Mujibur Rahman Tunnel serves as an underwater expressway beneath the Karnaphuli River