Soviet officials told 49,000 residents their evacuation would last 'approximately three days.' Most never went home — and the plant's molten core is still burning underground today.
On April 26, 1986, reactor 4 at the Chernobyl Nuclear Power Plant near the city of Pripyat in Soviet Ukraine exploded during a safety test that had gone catastrophically wrong. Operators had disabled key safety systems to run the test, and when they attempted a controlled shutdown, an uncontrolled nuclear chain reaction tore the reactor apart.
The explosion blew the 1,000-tonne reactor lid off the building and sent a plume of radioactive material across Europe. It remains one of only two nuclear accidents ever rated at the maximum level 7 on the International Nuclear Event Scale — the other being the 2011 Fukushima disaster in Japan.
Two engineers died in the initial blast. Within three months, 28 first responders — firefighters and plant workers who rushed to contain the disaster with little to no protective gear — died from acute radiation syndrome. In total, 134 workers were hospitalized with severe radiation exposure.
The city of Pripyat, home to 50,000 people and built specifically to house the plant's workers, was not evacuated until 36 hours after the explosion. Residents were told to pack only what they needed for three days. The city has been abandoned ever since, its Soviet-era apartment blocks, amusement park, and schools slowly being swallowed by the forest.
Over 500,000 personnel — known as 'liquidators' — were mobilized to contain and clean up the disaster. They included soldiers, firefighters, miners, and civilians from across the USSR, many of whom received significant radiation doses. The total cost has been estimated at US$700 billion, making it the most expensive disaster in recorded history.
The disaster's long-term health impact is still debated. By 2005, approximately 6,000 cases of childhood thyroid cancer had occurred in affected populations — most survivable, but a direct result of drinking contaminated milk in the days after the explosion. The WHO projected roughly 9,000 eventual cancer-related deaths across Ukraine, Belarus, and Russia.
Chernobyl is widely credited with accelerating the fall of the Soviet Union. Soviet leader Mikhail Gorbachev later wrote that the disaster revealed the rottenness of the Soviet system more starkly than anything else — the secrecy, the incompetence, the disregard for human life. The glasnost reforms that followed were partly inspired by the need to be honest about what had happened.
The Chernobyl Exclusion Zone — a 30 km radius around the plant — remains largely off-limits to this day, though it has paradoxically become a thriving wildlife sanctuary. Without humans, wolves, lynx, eagles, and even Przewalski's horses have repopulated the abandoned landscape.