74,000 years ago, the sun disappeared for a decade, and the human race nearly came to an end. This was the Toba Catastrophe—a super-eruption 5,000 times more powerful than Mount St. Helens. The explosion sent 2,000 cubic kilometers of ash into the atmosphere, triggering a brutal volcanic winter and a sudden ice age. Evidence hidden in our DNA reveals a terrifying genetic bottleneck: the entire global human population crashed to as few as 3,000 survivors. We came within a hair’s breadth of total