First settled by the Dorians in the 9th century BC, Ancient Thira consists of Hellenistic, Roman and Byzantine ruins and is an atmospheric and rewarding site to visit. The ruins include temples, houses with mosaics, an agora (market), a theatre and a gymnasium. There are splendid views from the site.
If you’re driving, take the narrow, switchbacked road from Kamari for 3km. Ancient Thira Tours runs an hourly minibus (9am to 1pm) from Kamari to the site (€10 return).
From Perissa, on the other side of the mountain from Kamari, a hot hike up a dusty path takes a bit over an hour to reach the site.