Harput Castle

Harput Castle, also known as Milk Castle, is a castle located in the historical Harput neighborhood within the borders of the current Elazığ Province, Turkey. It was built by the Urartians on a rectangular plan. The castle consists of two parts, internal and external. According to legend, a scarcity of water and abundance of milk during its construction meant that milk was added to the castle's mortar, leading to it being sometimes called "Milk Castle".

Source: Wikipedia