Qal'at Ja'bar

Qal'at Ja'bar (Arabic: قلعة جعبر‎‎, Turkish: Caber Kalesi) is a castle on the left bank of Lake Assad in Ar-Raqqah Governorate, Syria. Its site, formerly a prominent hill-top overlooking the Euphrates Valley, is now an island in Lake Assad that can only be reached by an artificial causeway. Although the hilltop on which the castle sits was possibly already fortified in the 7th century, the current structures are primarily the work of Nur ad-Din Zangi, who rebuilt the castle from 1168 onwards. Since 1965, several excavations have been carried out in and around the castle, as well as restoration works of the walls and towers. The castle was a Turkish exclave between 1921 and 1973.

• http://en.wikipedia.org/wiki/Qal'at Ja'bar