Pompeii depicts the 79 AD eruption of Mount Vesuvius, an active volcano located in the Bay of Naples in the south of Italy. The eruption of the volcano occurred on 24 August, 79 AD at around noon. At this time, the increasingly prosperous city of Pompeii was home to 15,000 citizens. Pompeii and the surrounding towns were built in the shadow of the volcano but, according to contemporary sources, the Romans believed the volcano to be extinct. In the lead-up to the eruption, small earthquakes were felt across the Bay of Naples. Pompeii had been badly damaged by a large earthquake 17 years before and seismic activity in the area was dismissed as a common occurrence. The pressure beneath the volcano continued to build until it burst through the rock at the top of the volcano.

Eye-witnesses described the eruption of Mount Vesuvius. They describe how a dark pillar of black smoke could be seen rising from the volcano. Vesuvius spat out smoke, ash, gas, and pumice stone. The black smoke blocked the sun from the sky as the volcano spewed more than a million and a half tons of debris into the air. The eruption is thought to have had more than 100,000 times the power of the nuclear weapons dropped on Nagasaki and Hiroshima at the end of World War II.