As of December 2010, the Channel Tunnel is the longest underwater tunnel in the world. The underwater part of the tunnel runs for 38 km and is composed of three tunnels linking England and France. Plans for the tunnel began as early as 1802, but the actual construction of the tunnel began in 1987 and lasted until the tunnel opened in 1994. The Channel Tunnel is considered to be a big contribution to engineering due to the immense difficulty of building it. The tunnel is used by train systems that operate between England and France and run some of the fastest trains in the world.
The Seikan Tunnel runs underneath Japan's Tsugaru Strait between the cities of Honshu and Hokkaido. The tunnel was created due to the severe weather that sometimes develops on the Tsugaru Strait, which killed 1,430 people riding ferry boats in 1954. The tunnel was extremely difficult to build due to the rock formations under the strait, which made workers incapable of using a tunnel boring machine to get through. The tunnel was completed in 1988 at a total cost of $7 billion and currently operates as a railway tunnel.
The Laerdal Tunnel is a 24.5 km tunnel in Norway that runs on the highway between the cities of Oslo and Bergen. This tunnel helped make this road considerably easier to navigate due to the many mountain and water crossings in Western Norway. The project was completed between the years of 1995 and 2000, and required extra safety efforts in certain portions of building due to cracked and non-solid rock formations.
