Chernobyl on HBO and Sky closely follows the nuclear disaster of the Chernobyl Power Plant in northern Soviet Ukraine. On April 26, 1986, a failed safety test coupled with design flaws and human error triggered the largest nuclear disaster in human history. The incident led to two explosions of Chernobyl’s Reactor Four, blowing out the roof of the reactor building and releasing up to five percent of the reactor’s nuclear material into the atmosphere. In the HBO and Sky drama, just moments after the Chernobyl explosion, a blue-white beam of light shot up into the sky from the exposed reactor core.