One volcanic eruption may have nearly wiped out the entire human species

About 74,000 years ago, the Toba supervolcano in Sumatra produced the largest eruption of the last two million years, burying South Asia under volcanic ash. Some scientists argue the resulting volcanic winter crashed human populations to just a few tens of thousands of survivors, though the theory remains disputed.

— Wikipedia contributors, Toba catastrophe theory — Wikipedia, human evolution and volcanology