Mosque of Abu el-Haggag

Luxor, Egypt (plan)

This 13th century AD or earlier mosque was built into the east wall of Ramesses' courtyard. Notice how high up the "ground level" is. All of Luxor temple used to be covered in sand up to this height, before excavation in the 19th century.

Abu el-Haggag was a 13th century AD Sufi saint who is buried in the mosque. He is associated with its preservation, not its original construction. A Wikipedia article recounts some of the legends associated with the saint.