Rather than bore a tunnel through the soil and rock below like the Channel Tunnel, the entire thing was prefabricated in sections and installed from the water surface above - a construction technique called immersed tube tunneling. Once a tunnel segment is secured in place, the bulkhead in the previous segment can be removed from the inside, allowing access inside the joint. Some of the most famous include the Øresund Link between Denmark and Sweden, the Busan-Geoje tunnel in South Korea, the Marmaray tunnel crossing the Bosphorus in Turkey, of course, the Fort McHenry tunnel in Baltimore I mentioned earlier, and the BART Transbay Tube between Oakland and San Francisco.