Kleftiko, Coastal rock formation in Milos Municipality, Greece.

Kleftiko is a coastal formation on the southwestern coast of Milos featuring three small bays bordered by white volcanic rocks. The site contains numerous sea caves and natural passages carved into the stone, creating a network of chambers and openings.

The name Kleftiko dates from the era of Mediterranean piracy, when the three successive coves served as a base for pirates attacking passing ships. The same caves offered shelter during bad weather. The rocks themselves are tuff and pumice layers formed about 3.1 million years ago, with basalt found nearby.

The name recalls the era of Mediterranean piracy, when the three coves served as a base for pirates attacking passing ships, and the caves gave shelter in bad weather. Local fishermen report that Mediterranean monk seals once used the caves to breed, though tourist traffic may have driven them away.

Kleftiko can be reached by excursion boat or on foot along a trail; boats also stop at Sykia, a cave on Milos' west coast whose roof has collapsed. There are no facilities on the rocks, so bring water and sun protection, and expect no shade among the white cliffs.

The white rocks were formed through volcanic activity and are constantly reshaped by water and wind erosion. This ongoing process means the formation looks different with each visit and visit season.