A pickup truck flees from the pyroclastic flows spewing from the Mt. Pinatubo volcano in the Philippines, on June 17, 1991. Behind it, the searing hot, bone-charring ash charges with the speed of a jet engine, preparing to swallow the car whole and burn the occupants alive. As you can see, it is a hot and dense cloud that is literally thousands of times bigger than the car it’s chasing. This was the second largest volcanic eruption of the 20th century.