About 74,000 years ago, humanity was faced with an extinction level event. This ancient super volcano erupted in Indonesia, and leaked 700 cubic miles of magma and shot a large volume of ash across the Indian Ocean, India and the South China sea. The cloud dispersed over 4,350 miles, blocking out the sun and making the atmosphere difficult to breathe.
Genetic research from that time shows that the amount of humans drastically decreased at that time. There could have been other factors involved, but scientists generally agree that a Supervolcano has the potential to wipe us out, if the eruption is large enough.