How many cities were destroyed by the eruption of Mount Vesuvius?

Three cities were destroyed when the volcano erupted.

They were Pompeii, Herculaneum, and Stabiae, all southeast of modern Naples.

When were the ruins of Pompeii discovered? Destroyed in A.D. 79, the city was not discovered until the late 1500s. Formal excavation did not begin until 1748.