: On April 26, 1986, a reactor at the Chernobyl Nuclear Power Plant in the Soviet Union exploded. It remains the worst nuclear accident in history, releasing radioactive material across Europe and leading to the long-term abandonment of the city of Pripyat.

: This major overhaul simplified the income tax code, eliminated many tax shelters, and significantly changed tax brackets for American individuals and corporations. Cultural and Technological Shifts Chernobyl Accident 1986 - World Nuclear Association

: Earlier that year, on January 28, the U.S. Space Shuttle Challenger disintegrated 73 seconds after liftoff, resulting in the death of all seven crew members, including teacher Christa McAuliffe.