The ruins of the 8th-century Ulu Cami, built by Marwan II, last of the Umayyad caliphs, is Harran's most prominent historic site. You'll recognise it by its tall, square and very un-Turkish minaret. It's said to be the oldest mosque in Anatolia. Near here stood the first Islamic university, and on the hillside above it you'll see the low-level ruins of ancient Harran, dating back some 5000 years.
The Ulu Cami was undergoing extensive restoration in 2019, which looked like it could be ongoing for the next few years. You can still see the site from above during the works.
