https://www.cnn.com/travel/article/fehmarnbelt-longest-immersed-tunnel-cmd/index.html
Descending up to 40 meters beneath the Baltic Sea, the world's longest immersed tunnel will link Denmark and Germany, slashing journey times between the two countries when it opens in 2029.
https://www.cnn.com/travel/article/fehmarnbelt-longest-immersed-tunnel-cmd/index.html
Denmark and Germany now building the world's longest immersed tunnel
www.cnn.comDescending up to 40 meters beneath the Baltic Sea, the world's longest immersed tunnel will link Denmark and Germany, slashing journey times between the two countries when it opens in 2029.