Ankara: An ancient sunken castle has been discovered in Turkey's Lake Van, according to a team archaeologists. The team from the Van University announced the discovery on Thursday. It is an ancient castle preserved deep within the lake, the biggest in Turkey and the second in the Middle East, in rather good condition.

Tahsin Ceylan, head of the team, said: "There was a local rumour that there might be something under the water but most archaeologists and museum officials told us that we won't find anything.

"We have been doing research in Lake Van for 10 years and the discovery was also unexpected for us."

The castle spans around a kilometre, with walls standing as high as three or four metres, kept in good condition by the alkaline waters of the lake. The fortress's remaining structures range from loose piles of stones to smooth square walls.

There's still a lot to find out about the castle. For example, it was still unclear how far the walls are buried in the sediment at the bottom of the lake. Further archaeological research should help to learn more clues about the people who build it.

The researchers first announced that they believe it is a Iron Age relic of the lost Urartu civilisation, also called the Kingdom of Van, which thrived in the region located near modern day Iran from the 9th to the 6th centuries B.C.

Last year the team also discovered a four-square-kilometre field of stalagmites, which they call "underwater fairy chimney" under the lake, and gravestones from the Seldjouk area, some 1,000 years ago.

Earlier this year they announced the discovery of a Russian ship believed to be sunk in 1948.