Some 75,000 years ago a super-eruption from the site of Lake Toba in Sumatra blasted out more than 200 cubic miles of ash and volcanic debris. Now, NGC investigates the devastating aftermath of one of the most powerful volcanoes of the last 2 million years, including the fascinating theory that it triggered a human genetic bottleneck - leaving a population of as little as a few thousand survivors to preserve the entire human race.
