Thíra or Thera, volcanic island (1991 pop. 9,360), c.30 sq mi (80 sq km), SE Greece, in the Aegean Sea. One of the Cyclades, Thíra is also known as Santorini, for St. Irene, the protector of the island. It is a tourism center noted for its wine. Pumice stone and powdered tufa are exported. It was the site of an enormous ancient volcanic explosion rivaling that of Tambora.

According to tradition, the island was first settled by Phoenicians and later by Laconians under the leader Thera. In the Bronze Age, Thera came under the influence of Crete (see Minoan civilization), but a devastating volcanic eruption (c.1645 B.C.) buried the island's settlements and threw massive amounts of dust into the earth's atmosphere, affecting the weather worldwide. It was resettled and later occupied (9th cent. B.C.) by the Dorians. In 631 B.C. colonists from the island founded Cyrene in N Africa.

Excavations in the E Mediterranean show that ash from the ancient eruption spread over Anatolia and parts of Egypt. It is theorized by some experts that the effects of the eruption were the catalyst for the collapse of Minoan civilization in the subsequent two centuries. Excavations at a Minoan site on Thíra have uncovered many well-preserved frescoes. Some controversial theories have equated ancient Thera with Atlantis.

ancient Thera formerly Santorini

Island, southern Cyclades, Greece. The remaining half of an exploded volcano, it surrounds a lagoon with volcanic cliffs rising to almost 1,000 ft (300 m). It was settled in the Bronze Age; Minoan remains date to before 2000 BC. One of the largest known volcanic eruptions occurred on the island circa 1500 BC, depositing ash and pumice as far away as Egypt and Israel. The eruption has been linked to such phenomena as the miracles of the Exodus and the sinking of Atlantis. Excavations have revealed a rich Minoan city buried under the volcanic debris. It was resettled by Dorian invaders circa 1000 BC.

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