Turkish President Recep Tayyip Erdogan on Saturday launched the start of construction on a controversial canal aimed at easing congestion on the Bosphorus but which critics say courts environmental disaster.
The "Canal Istanbul" is a gigantic waterway running parallel to the Bosphorus Strait connecting the Black Sea to the Sea of Marmara and the Mediterranean.
"Today we are opening a new page in the history of Turkish development," Erdogan said during the ceremony to lay the foundation stone of a bridge forming part of the project.
The 45 kilometre (28 mile) long waterway will connect the Black Sea to global maritime networks, a strategically important issue at the heart of European geopolitics and conflicts for centuries.
Erdogan's detractors accuse him of clinging to a project that will lead Turkey to ecological disaster and debt as massive as it is unnecessary.
Erdogan devoted almost all of his speech to defending the project.
Citing the risks posed by the rising number of ships passing through the Bosphorus, Erdogan said the project was mostly aimed at "ensuring the safety of (Turkey's) citizens in Istanbul" and allowing the country to take "a more important place" in international trade.
Dismissing critics, he said: "All stages of the project have been designed in accordance with science."
The project has also sparked criticism abroad, mainly in Russia, a country that fears seeing easier access to the Black Sea for NATO forces.
Under the Montreux Convention governing navigation through the Bosphorus Strait -- the only natural maritime access to the Black Sea -- countries that don't have a coastline to the waters must give advanced notification of plans for their ships to pass through the region. And then, the vessels can only stay for a limited time.
"This project in no way violates Montreux," said former Prime Minister Binali Yildirim, who spoke before Erdogan at the ceremony.