World’s longest undersea A massive engineering project is underway to revolutionize Europe’s transportation system. The Fehmarnbelt Tunnel, which is being built under the sea, will connect Denmark and Germany. When completed, it will be the world’s longest road and rail tunnel and the longest submerged tunnel. Khabar Express Tribune. The 18-kilometer (11.2-mile) tunnel will carry two roadways and two electric railway lines. While tunnels are traditionally built by digging through hard ground, the Fehmarnbelt Tunnel is being built using prefabricated concrete sections. The massive sections will be floated to the…
Read MoreWorld’s longest undersea tunnel: Denmark-Germany to meet in 2029
