The castle has 13ft walls and the site spans more than a kilometer - but no-one ever believed it existed despite local rumours of secrets hidden beneath the surface
A forgotten underwater fortress has been discovered by a team of archaeologists 3,000 years after it was flooded in a lake.
During a recent dive to explore the lake, archaeologists from Van Yüzüncü Yil University and a team of independent divers found an underwater fortress.
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.
Video shot by Ceylan shows the underwater archaeologists swimming through the turquoise blue lake. Large stones stacked together like a brick wall puncture the lake's waters. The fortress's remaining structures range from loose piles of stones to smooth square walls.
“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.
“The walls of this castle cover a wide section. The excavations need to be done underwater but we don’t know how deep the walls are. A three to four meter wall section can be seen and the castle ruins cover an area of one kilometer. Since the water of Lake Van is alkaline, the castle has not been damaged and has kept its characteristics underwater. We have detected the castle’s exact location and photographed it and have made progress in our research. We now believe we have discovered a new area for archaeologists and historians to study,” Ceylan said.
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.