Avrasya Tuneli, built underneath the seabed of Bosphorus

Located in Istanbul, the capital of Turkey, Eurasia Tunnel links Kazlıçeşme (on the European side) and Göztepe (on the Asian side of the city). The tunnel was built underneath the seabed of Bosphorus and contributes to the solution of the traffic problem between the two continents.

Avrasya Tuneli

Opened to traffic on Tuesday 20th December 2016, the tunnel, with two decks and two lanes per deck, is 14.5 km long with a 5.4 km of the route under the seabed of Bosphorus, also known as the Istanbul Strait. It is open on all days, in all weather conditions. Tunnel excavations started on April 19, 2014. The toll tunnel is asphalted but pretty steep. Its deepest part is 106.4 meters below the sea level.

The speed limit is 70 km/h (43 mph). A daily average of around 120,000 cars and light vehicles pass through the tunnel, which significantly improved commuting times for citizens and businesses in the city. The maximum height for the vehicles is 2.8 meters. It’s built as resistant to an earthquake measuring 9 on the Richter scale.
Pic: https://www.businessistanbul.com/avrasya-tuneli-trafige-acildi/?lang=en