Scientific analysis left|thumb|Pompeii and Herculaneum, as well as other cities affected by the eruption of Mount Vesuvius. The black cloud represents the general distribution of ash, pumice and cinders. Modern coast lines are shown. Reconstructions of the eruption and its effects vary considerably in the details but have the same overall features. The eruption lasted two days. The morning of the first day was perceived as normal by the only eyewitness to leave a surviving document, Pliny the Younger. In the middle of the day, an explosion threw up a high-altitude column from which ash and pumice began to fall, blanketing the area. Rescues and escapes occurred during this time. At some time in the night or early the next day, pyroclastic surges in the close vicinity of the volcano began. Lights were seen on the peak, interpreted as fires. People as far away as Misenum fled for their lives. The flows were rapid-moving, dense and very hot, knocking down, wholly or partly, all structures in their path, incinerating or suffocating all population remaining there and altering the landscape, including the coastline. Additional light tremors accompanied these and a mild tsunami in the Bay of Naples. By late afternoon of the second day, the eruption was over, leaving only haze in the atmosphere through which the sun shone weakly.
Scientific analysis left|thumb|Pompeii and Herculaneum, as well as other cities affected by the eruption of Mount Vesuvius. The black cloud represents the general distribution of ash, pumice and cinders. Modern coast lines are shown. Reconstructions of the eruption and its effects vary considerably in the details but have the same overall features. The eruption lasted two days. The morning of the first day was perceived as normal by the only eyewitness to leave a surviving document, Pliny the Younger. In the middle of the day, an explosion threw up a high-altitude column from which ash and pumice began to fall, blanketing the area. Rescues and escapes occurred during this time. At some time in the night or early the next day, pyroclastic surges in the close vicinity of the volcano began. Lights were seen on the peak, interpreted as fires. People as far away as Misenum fled for their lives. The flows were rapid-moving, dense and very hot, knocking down, wholly or partly, all structures in their path, incinerating or suffocating all population remaining there and altering the landscape, including the coastline. Additional light tremors accompanied these and a mild tsunami in the Bay of Naples. By late afternoon of the second day, the eruption was over, leaving only haze in the atmosphere through which the sun shone weakly.