How many volcanoes in Italy erupted during the 20th century?

There are three currently active volcanoes in Italy: Etna, Stromboli and Vesuvius. All three of them erupted in the twentieth century; Etna and Stromboli continue to erupt regularly in our own century.

Mount Vesuvius is also considered active, although it has not had a major eruption since 1944. Today, potential future eruptions continue to pose a threat to the cities that surround it including Naples. It is regarded as one of the most dangerous volcanoes in the world because of the population of 3,000,000 people living near enough to be affected by an eruption, with 600,000 in the danger zone, making it the most densely populated volcanic region in the world. It has a tendency towards violently explosive eruptions, which are now known as Plinian eruptions.

Vesuvius is known for some of the most famous volcanic explosions in European history. It has erupted eight times since the beginning of recorded history. Its deadliest eruption occurred in the year 79 AD, destroying the nearby cities of Pompeii and Herculaneum.

In March 1944, Vesuvius erupted destroying nearby villages. The United States Army Air Forces 340th Bombardment Group was based at Pompeii Airfield just a few kilometres from the eastern base of the volcano. The tephra and hot ash from multiple days of the eruption damaged the fabric control surfaces, the engines, the Plexiglas windscreens and the gun turrets of the 340th's B-25 Mitchell medium bombers. Estimates ranged from 78 to 88 aircraft destroyed.