The volcano Vesuvius buried Pompeii and Herculaneum in 79 AD. By today's standards these would be considered smallish cities, containing about 5000 (Herculaneum) and 20,000 (Pompeii) residents. But now Vesuvius hosts a large city which sprawls up its flanks: Naples (Napoli). It contains 1.2 million people. If Vesuvius repeats the 79 AD performance, the loss of life and property will be staggering.
Mount Etna: Unlike Vesuvius, no large city straddles its slopes, but there are still many towns and communities in the area. Catania, population 350,000 is a short distance south-southeast of the volcano.
Etna in action: