The £2.8bn world’s longest underwater tunnel that will connect Europe and Asia

Turkey is investing billions of pounds in upgrading its transport infrastructure, as it seeks to boost its domestic economy.

One major project underway is the Great Istanbul Tunnel, with construction having started last year.

The transport link will run for 6.5 km (4 miles) under the Bosphorus, connecting the European and Asian parts of Istanbul.

The tunnel is expected to cost a cool £2.8 billion and is scheduled to open to the public in 2028.

Once fully operational, the tunnel will carry an estimated 1.3 million passengers per day.

Sitting at 110 metre below sea level, the tunnel will be 18.8 metres in diameter and able to accommodate both cars and trains.

Divided into three tiers, two will be for cars and one for trains, according to the most recent plans.

Cars will be able to travel at speeds of up to 120kmh though the tunnel, while trains will travel at top speeds of 160kmh.

The tunnel will connect the highways between Istanbul’s three airports: Istanbul Atatürk Airport, Sabiha Gökçen Airport, Istanbul Airport.

The railway section will consist of 13 stations, accommodating 70,000 passengers per hour.

It will also connect with 11 other railways, and allow the Metrobus line, a crucial part of Istanbul’s transportation system, to function at optimal capacity.

The construction of the tunnel is viewed as a strategic project of significant economic and social importance.

Economically, the tunnel is expected to enhance trade and tourism between Asia and Europe.

It will also create new job opportunities and stimulate economic growth in Turkey.

Socially, the tunnel will reduce traffic congestion in Istanbul, thereby improving the quality of life for city residents and reducing environmental pollution.

Ministers claim it will be the world’s longest underwater tunnel. However the 18km (11 miles) Fehmarnbelt tunnel between Denmark and Germany is currently under construction, due to be completed in 2029.