Pompeii, Italian Pompei, ancient city of Campania, Italy, 14 miles (23 km) southeast of Naples, at the southeastern base of Mount Vesuvius. It was built on a spur formed by a prehistoric lava flow to the north of the mouth of the Sarnus (modern Sarno) River. Pompeii was destroyed, together with Herculaneum, Stabiae, Torre Annunziata, and other communities, by the violent eruption of Mount Vesuvius in 79 ce. The circumstances of their destruction preserved their remains as a unique document of Greco-Roman life. Pompeii, Herculaneum, and Torre Annunziata were collectively designated a UNESCO World Heritage site in 1997.