Chernobyl Nuclear Reactor Disaster

On April 26, 1986, furnace number four at the Chernobyl nuclear power plant caused a meltdown and explosion. Historically, it was the world's worst nuclear power plant disaster. Radioactive material poured down on Ukraine, Belarus, and Russia. The amount of radioactive material is said to have been about 500 times the amount caused by the atomic bomb dropped on Hiroshima.