Most of the people who lived near Vesuvius in A.D. 79 thought of it as simply a very big hill. However, Vesuvius was really a sleeping volcano, silently and slowly building up pressure until it would one day explode.
Vesuvius had been active in the eighth century B.C. But between that time and A.D. 79—over 800 years—it had remained dormant (not active). That, in part, explains why no one gave much thought to this lovely hill on the outskirts of town.
During those 800 seemingly calm years, however, Vesuvius was quietly simmering. Pressure was building up, because there was no outlet for the gases inside the volcano.
