The Chernobyl nuclear disaster occurred on April 26, 1986, at the Chernobyl Nuclear Power Plant in Ukraine. A reactor explosion released large amounts of radioactive particles into the atmosphere, affecting surrounding areas and spreading across Europe. The disaster was caused by a flawed reactor design and operator errors during a safety test. In the aftermath, the Soviet government evacuated over 100,000 people from the nearby town of Pripyat and established a 30-kilometer exclusion zone. The incident led to significant changes in nuclear safety regulations worldwide and raised awareness about the potential dangers of nuclear energy.