The days prior to the eruption were recorded by a Roman administrator named Pliny the Younger. Pliny wrote that there had been several earth tremors in the days leading up to the eruption, but Roman science didn't know that earthquakes could signal the start of a volcano erupting. Even when they first saw smoke rising from the top of the mountain, they were merely curious. They had no idea what was coming until it was too late.
Then at 11pm the huge cloud hanging above the volcano collapsed from its own weight and blasted the town in six devastating waves of super-heated ash and air which asphyxiated and literally baked the bodies of the entire population. Still the ash kept falling and relentlessly the once vibrant city was buried metres deep, to be lost and forgotten, wiped from the face of the Earth.