The Turkish president on Saturday inaugurated the huge Ilisu Dam in the country's southeastern province Mardin.
Its total water storage volume is 11 billion cubic meters and can generate 1,200 megawatts of hydroelectricity.
Addressing the opening ceremony, Recep Tayyip Erdogan said the project has been completed despite obstacles, including financing issues and terror attacks.
'This work is the best answer to sworn enemies of Turkey and those who're hostile to their own country and the nation,' Erdogan said.
He said it is the largest dam on the Tigris River, and the fourth largest Turkish hydroelectric plant.
'This dam is the second-largest dam in the country after Turkey's Ataturk Dam, and the largest in the world in terms of filling volume among the 'concrete faced rockfill dam' types,' the president said.
Saying the project cost 20 billion Turkish liras ($2 billion), he argued that its contributions to the Turkish economy will be around 3 billion Turkish liras ($309 million) annually.
Reporting by Zafer Fatih Beyaz
Writing by Gokhan Ergocun