Ancient Eleusis is a small archaeological site on the southern slope of Gavrilos Hill, near Perissa. Rock-cut tombs from about 400-200 BC, carved niches, an altar, traces of a catacomb or temple, and a snake relief are visible in the rock.
The site is modest, but it gives a quieter look at ancient Thera beyond the better-known ruins at Akrotiri. It is best combined with time in southern Santorini rather than treated as a long standalone trip.