Pompeii

On 24 August 79 CE (a date now disputed in favour of a likely autumn date based on later finds), Mount Vesuvius erupted with a force that buried the Roman city of Pompeii under several metres of volcanic ash and pumice within about 18 hours, followed by pyroclastic surges of superheated gas and debris that killed those who had remained. The eruption was recorded by Pliny the Younger in two letters to the historian Tacitus, the only surviving eyewitness account of a Roman volcanic eruption and the source of the term "Plinian eruption" used by volcanologists today.

The ash that buried Pompeii sealed the city in a layer that excluded air and moisture, preserving buildings, wall paintings, mosaics, graffiti, bread still in ovens, and even the political campaign slogans painted on walls. From 1863, excavator Giuseppe Fiorelli developed the technique of pouring plaster into the cavities left in the hardened ash by decomposed bodies, producing detailed casts of the postures of victims at the moment of death — a method still used today, with CT scanning of the casts since the 2010s revealing details of the victims' teeth, bone structure, and even the fabric of their clothing. Excavation continues into the 21st century, with new houses, frescoes, and even a still-life painting resembling a modern pizza uncovered as recently as the 2020s — roughly a third of the city remains unexcavated, deliberately left for future archaeologists with better techniques.