Around 71,000 years ago, Mount Toba erupted on the island of Sumatra in what is now Indonesia. This was not your ordinary volcanic eruption. No, this was the second largest known eruption in the last 450 million years, displacing 4,000 times as much earth and ash as the familiar Mount St. Helens eruption. The result seems to have been six years of "volcanic winter", which not only triggered an Ice Age that lasted 1,000 years but also caused massive deforestation, famine for all living things, and a major die-off of human beings. The latest genetic research indicates that the human population got as low as 2,000 individuals in Africa. Yes, that's two thousand -- a little more than the population of my hometown in Maine. There may have been isolated pockets of modern humans elsewhere (again most likely in Africa), but it appears that virtually all of the genetic and racial diversity we see today derives from an extremely small population of humans who survived a serious climatic crisis 3,000 generations ago. In other words, we barely made it!