On April 26, 1986, two powerful explosions tore through Unit 4 of the Chernobyl nuclear power plant, flipping the reactor's giant 2,000-ton concrete lid into the air like a coin. White-hot chunks of the nuclear core rained down on adjacent buildings, setting fires and peppering the ground outside. Remnants of the core burned for 10 days, churning a thick plume of radioactive isotopes equivalent to 400 Hiroshima bombs high into the atmosphere.
