There are three main types of volcanoes: active volcanoes that currently erupt like Kilauea in Hawaii, dormant volcanoes that are currently sleeping like Mount Fuji in Japan, and extinct volcanoes that cannot erupt again like Vesuvius in Italy. The eruption of Vesuvius in the past buried the city of Pompeii under ash, where its ruins were later discovered. Underwater volcanoes can form new islands as they erupt, like the Galapagos Islands off the coast of Ecuador which were formed under the sea and still have eruptions.