Herculaneum was a smaller town (approximately 5000 people) with a wealthier population than Pompeii at the time of their destruction. After the eruption of Mount Vesuvius in 79 AD, the town of Herculaneum was buried under approximately 20 meters (50-60 feet) of lava, mud and ash. It lay hidden and nearly intact for more than 1600 years until it was accidentally discovered by some workers digging a well in 1709. From there, the excavation process began but is still incomplete. Herculaneium became famous as the source of the first Roman skeletal and physical remains available for study that were located by science, for the Romans almost universally burned their dead. Since the discovery of bones in 1981, some 150 skeletons have been found, most along the sea shore.
The surprisingly good state of preservation of the structures and their contents is due to three factors:
- By the time the wind changed and ash began to fall on Herculaneum, the structures were already filled with volcanic debris. Thus the roofs did not collapse.
- The intense heat of the first pyroclastic flow carbonized the surface of organic materials and extracted the water from them.
- The deep (up to 25 meters), dense tuff formed an airtight seal over Herculaneum for 1,700 years.