Two levels will house roads, with the third a metro rail route. The section with both road and metro in spans 16.8m in diameter and will run for 6.5km below the sea. The sea is approximately 65m deep in this part of the Bosphorus.
According to Turkish Prime Minister Ahmet Davutoglu the project, which last month he named "Grand Istanbul Tunnel" would be the first of its kind in the world.
Tendering should be complete in time for Turkey’s general election on 7 June. The aim is to open the tunnel in 2020. "Istanbul is a city which shapes history, it deserves the best, including mega-projects" Davutoglu said, while presenting the new project in an event organized by the Ministry of Transportation. "The three-level mega project will be the signal flare of the Turkish Republic, the fourth global state in Istanbul after three empires,"
