The document summarizes the impacts and history of several nuclear disasters around the world, including Chernobyl, Three Mile Island, Fukushima, and others. It notes that the long-term effects of radiation exposure could include constant mutations in human DNA. It provides locations and basic timelines of major nuclear events. The Chernobyl disaster of 1986 in Ukraine and Russia is described as one of the worst nuclear disasters in history due to its large exclusion zone and long-term effects on the region.