Mount Vesuvius near Pompeii, Italy, begins to erupt on this day in the year 79; within the next 25 hours, it wipes out the entire town. Hundreds of years later, archaeologists excavated Pompeii and found everything and everyone that had been there that day perfectly preserved by the volcano's ash.

Pompeii, about 90 miles south of Rome, was established in 600 B.C.E. in the shadow of Mount Vesuvius, which stood approximately 6,500 feet high. Apparently, no one was aware that Vesuvius was an active volcano, even after an earthquake in February of the year 63.

The preserved remains of Pompeii are not the only evidence of the disaster. Two authors who witnessed the eruption also recorded their observations. Pliny the Elder was across the bay from Vesuvius on the morning of August 24 when a large cloud was noticed emanating from the volcano. He dispatched several ships to the coastal town of Resina to investigate, but the ships could not land because they were pelted by flaming rocks from the volcano. Pliny the Elder headed toward the town of Stabiae, where ash continued to fall through the night. By the following morning, the ash even obscured the sun from view. On August 25, Pliny the Elder died, apparently overtaken by sulfur gases released from the volcano.

Pliny the Younger, just 18 years old at the time, was also a witness to the eruption. He reported people climbing through waves of ash to escape. His account of the tons of pumice, rock and ash that Vesuvius pumped out over a 25-hour period, combined with the evidence left in Pompeii, indicates that about 2,000 residents of Pompeii survived the initial eruption of Vesuvius on August 24. It was the following morning when another, more powerful eruption killed everyone in an instant. When rain mixed with the ash, it formed a sort of concrete, preserving the city. The town of Herculaneum was also buried on August 25, but by a mudslide set off by the eruption and accompanying tremors. It is estimated that 13,000 people in total died from the eruption.

It was not until 1595, during the construction of an aqueduct, that Pompeii was rediscovered. Unfortunately, what can be viewed today is only a small fraction of what was found then, as looting and pillaging over the years has greatly reduced the archaeological value of the site. Some scientists believe that there may still be other villages buried by Vesuvius that have yet to be discovered.