A pyroclastic surge - a deadly, fast-moving avalanche of searing gas and rock fragments - made its way toward Herculaneum. People, who thought they would be safe on the beach, were not. All died from the enormous heat, essentially turned into charcoal. For them, at least, death was instantaneous.
Inside the boat houses, however, people died from thermal shock. Teeth and bones were shattered in the boiling material which descended upon them. Three hundred men, women and children were found in Herculaneum's boat houses. They had remained there, for thousands of years, until their remains were discovered by archaeologists.
When Vesuvius' magma chamber collapsed, triggering another pyroclastic surge, the toxic materials headed straight for Pompeii. Still, inhabitants of the city were not all killed. The city was not yet buried.
The worst was still to come.
Copyright BBC, all rights reserved. Clip provided here as fair use for educational purposes and to acquaint new viewers with the program.
The film is based, in part, on Pliny the Younger's letters about the Vesuvius eruption. It uses computer-generated images to recreate what the eruption must have been like for the residents of Pompeii. Online, via BBC's Channel at YouTube.
Tim Pigott-Smith (Pliny the Elder)
Alex Furguson (Pliny the Younger)
Katherine Whitburn (Julia)
Jim Carter (Polybius)