A massive stone structure on top of a hill on the edge of a lake

Qal'at Najm (Arabic: قلعة نجم‎‎) is a castle located on the right bank of the Euphrates, near the town of Manbij (Syria). The castle probably stood on the site of an earlier Roman site and is known from Arabic texts since the 7th century CE. Reconstruction works were carried out in the castle by Nur ad-Din Zangi and Az-Zahir Ghazi during the 12th and early 13th centuries. The castle sits on a mound that is protected by a glacis and houses a palace-bath complex and a mosque.

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