Therasia

Therasia a small island across of Oia formed as part of the same volcanic system as Santorini. Before about 1600 BCE, Santorini was a nearly circular island. The massive Minoan eruption caused the central part of the island to collapse, creating the caldera.

This collapse split the original landmass into separate islands—Santorini (Thira), Therasia, and later the smaller volcanic islets Nea Kameni and Palea Kameni formed from subsequent eruptions.

Therasia represents a preserved fragment of the original outer rim of that ancient volcano. Its quieter, less-developed character today contrasts with Santorini’s busy towns, offering a glimpse of how the island may have looked before the catastrophic eruption reshaped the region.