Undersea Tunnel Connects Europe and Asia

A tunnel running from Istanbul, Turkey, under the Bosporus Strait has opened to vehicle traffic and now connects the Asian and European continents.

The twin-deck Eurasia Tunnel reduces driving time across the Strait from the current 100 minutes via bridge to 15 minutes.

The tunnel is 14.6 kilometers (nine miles) long, including the 5.4 kilometer (3.4 mile) section beneath the Strait which separates Asian Turkey from European Turkey. The Bosporus is the world’s narrowest strait used for international navigation and connects the Black Sea with the Sea of Marmara.

About 120,000 cars are expected to use the highway tunnel daily, and this is expected to reduce traffic congestion in Istanbul significantly. 

SK Engineering won the $1.24 billion contract to build the tunnel, along with Turkish firm Yapi Merkezi, in 2008, and the consortium started work on the project in January 2013.

Construction involved digging 100 meters (330 feet) under water, and the project was completed three months ahead of schedule. SK Engineering deployed the world’s largest tunnel boring machine, with a diameter of 13.7 meters (45 feet) and a length of 120 meters (394 feet). Each day, the machine moved forward seven meters, digging up enough earth and sand from the seafloor to fill an average of 100 25-ton trucks.

SK Engineering will operate and maintain the tunnel until 2041.