Pompeii and Herculaneum were Roman cities built on the sides of Mt. Vesuvius. When Vesuvius erupted, both cities were covered in ash. It happened so quickly that people in these two cities didn't have time to get out. For almost two thousand years, the cities remained buried under the ash.
When archaeologists finally found and dug out the two cities, they found bread in ovens where it had been baking. They found the mummified remains of some people in the temples, where they had gone to pray for deliverance. The eruption and efforts to rescue the people were recorded by Pliney the Younger. His records have survived to modern times.