A forgotten underwater fortress has been discovered by a team of archaeologists 3,000 years after it was flooded in a lake.
The site of the ancient building measures nearly 1km across and the walls are up to 13ft hight.
It was found by expert divers in Turkey's Lake Van, in the east of the country near the Iranian border.
The lake did not exist during the time of the Iron Age Urartu civilisation, which spanned parts of modern day Turkey, Armenia and Iran and whose people built the castle.
Large Urartu ruins that predate the lake also stand around its shores, but the fortress is completely submerged.
National Geographic reported the fortress was found by explorers from Van Yüzüncü Yil University, working alongside expert divers.
Tahsin Ceylan, head of the diving team, said the explorers were told there was little left to find beneath the waters of Lake Van.
But they pressed ahead based on local rumours about buries treasures below the surface.
Videos show the divers swimming in the clear blue waters and inspecting the brick walls of the fortress.
"Studies were done on the underwater portion of the historic Urartian castle in our city, revealing it to be nearly 3,000 years old," Adilcevaz district governor Arif Karaman told Hurriyet Daily News .
Ceylan added: "It is a miracle to find this castle underwater. Archaeologists will come here to examine the castle's history and provide information on it."
The ancient inhabitants of Lake Van moved as the water levels began to rise.
Lake Van is now 74 miles across and has a maximum depth of 1,480ft.