Qasr Kharana (Arabic: قصر خرّانة), sometimes Qasr al-Harrana, Qasr al-Kharanah, Kharaneh or Hraneh, is one of the best-known of the desert castles located in present-day eastern Jordan, about 60 kilometres (37 mi) east of Amman and relatively close to the border with Saudi Arabia. It is believed to have been built sometime before the early 8th century AD, based on a graffito in one of its upper rooms, despite visible Sassanidinfluences. A Greek or Byzantine house may have existed on the site. It is one of the earliest examples of Islamic architecture in the region.
Its purpose remains unclear today. “Castle” is a misnomer as the building’s internal arrangement does not suggest a military use, and slits in its wall could not have been designed for arrowslits. It could have been a caravanserai, or resting place for traders, but lacks the water source such buildings usually had close by and is not on any major trade routes.
It remains very well preserved, whatever its original use. Since it is located just off a major highway and is within a short drive of Amman, it has become one of the most visited of the desert castles. Archaeologist Stephen Urice wrote his doctoral dissertation, later published as a book, on Qasr Kharana, based on his work restoring the building in the late 1970s.
Source : Wikipedia