Built in the 9th century BC, Resafa was a desert outpost then a city located in the Roman province of Euphratensis, in modern-day Syria. Its ramparts and buildings were erected by Emperor Justinian.
Resafa was a major stop on the caravan routes linking Aleppo, Dura Europos, and Palmyra. However, since there was no spring or running water, it depended on large and impressive underground cisterns to capture the winter and spring rains.
Resafa's original name, Sergiopolis, is a reference to Saint Sergius, a martyred Christian soldier who was buried there. In the 4th century, it became a major Christian pilgrimage center.
Resafa is now an archaeological site near the city of Ar Raqqah. It has well preserved walls and ruins. The Basilica of Saint Sergius, in particular, is not something you would expect to see in the middle of a desert!