Qasr al-Hayr al-Sharqi (Eastern al-Hayr Palace or the "Eastern Castle") is a castle in the middle of the Syrian Desert. It was built by the Umayyad caliph Hisham ibn Abd al-Malik in 728-29 CE in an area rich in desert fauna. It was apparently used as a military and hunting outpost. The palace is the counterpart of Qasr al-Hayr al-Gharbi, a nearby castle palace built one year earlier.
Read more about Qasr Al-Hayr Al-Sharqi: Location, Architecture, World Heritage Status