It was an April night, and most people were already asleep in bed. Nothing was out of the ordinary. No one had any reason to feel unsafe. The world was not prepared for humankind’s biggest nuclear disaster. But that’s exactly what happened in the wee hours of April 26, 1986. Tucked away in a corner of the Soviet Union, as the Cold War was finally coming to its end, something horrible was happening that would make the world stop and take notice.

The world didn’t have any other choice but to rally around the USSR when Chernobyl dissolved in disaster. It was a terrible catastrophe of epic proportions, and even decades later the images of this event are horrifyingly chilling. The effects of Chernobyl are still being felt by millions, and will continue to be felt for generations to come. This disaster hasn’t stopped unfolding since that fateful April day in 1986.

It has taken the efforts of the world to protect the Earth from Chernobyl, and the world will have to continue to heal itself long after everyone who remembers this disaster has gone. But forgetting Chernobyl is the most dangerous thing mankind can do…because this part of the world will continue to be a threat to us for tens of thousands of years.

20. It All Happened Quickly

Things were going normally that April night in 1986 that would eventually become a black mark on the pages of history. Workers were going about their business performing a systems test on reactor number 4 at around 1 in the morning. Then, a sudden surge of power changed the course of history. An emergency shutdown was attempted after the power surge, which only made matters worse. An even more extreme power spike caused the reactor to rupture, and it created a series of explosions. The reactor was ignited, and a huge plume of radiative smoke bellowed forth into the air. The flames kept burning until rescue crews dumped massive amounts of sand onto the site by helicopter.

19. Nearby Residents Were Left in Danger

Pripyat was built specifically to house Chernobyl workers, so this small, prosperous town was closest to the danger zone. However, the people here were not evacuated to safety right away. They saw the smoke coming from the power plant, but they were told it was simply routine discharge. And so, they carried on with their daily lives even as they were being poisoned by radiation. People began to get ill within hours of the explosion. It wasn’t until the 27th that buses arrived to take residents away from town and evacuate them to safety. They were told at midday they must leave town. Most would never return, though there were instructed to take only what they might need for the next three days.

18. 30 People Died Within 1 Month

On the night of the explosion, two workers inside the power plant died. Within a few weeks, 28 more people died due to acute radiation poisoning. When Chernobyl melted down, at least 5 percent of the reactor core was released into the atmosphere. That’s 5200 PBq, for the scientists out there. There has been an increase of thyroid cancer in the area, according to the World Nuclear Association, as a result of the lingering radiation. A total of 134 people were confirmed to receive radiation poisoning directly from the event. Hundreds of thousands were ultimately affected by the Chernobyl disaster.

17. It Didn’t Have to Happen At All

The sad truth is, Chernobyl was a completely preventable disaster. The reactor design was flawed from the very beginning. If someone had caught the error and re-designed the flawed system, the power plant could have functioned perfectly for decades. Because Chernobyl was also manned by personnel who did not receive adequate training, it all became a recipe for disaster one dark night in 1986. Chernobyl was headed for horror from its earliest days, but with just a little more care and attention the catastrophe could have been completely avoided. It’s terrifying to know that the Chernobyl tragedy never had to happen at all.

16. Residents Are STILL Being Resettled

Though the Chernobyl disaster occurred in 1986, resettlement of the population around the site is still ongoing. By May 14, 1986, 116,000 residents of nearby Pripyat were evacuated from their homes. Only 1,000 came back to the area to live within the contaminated zone. Most of them received only low doses of radiation as a result. More than 220,000 people were resettled after Chernobyl. The new town of Slavutich was created for the people of Pripyat who were forced to evacuate their homes. In 2005, around 211 villages were reclassified to have fewer settlement restrictions. In 2010, Belarus announced that it would resettle thousands of people back into the contaminated area.

15. It Contaminated Three Countries

To this day and for the foreseeable future, a large part of Russia and the Ukraine are still under the effects of radiative fallout. Huge parts of Russia, Belarus and Ukraine have been affected and will continue to be affected by the radiation. These three countries felt the brunt of the disaster, but Chernobyl spread far and wide. The Chernobyl disaster was so big, parts of Europe and Scandinavia also felt some minimal effects of the event. The exclusion zone around Chernobyl covers more than 100,000 acres or land, a huge area of the Earth that will not be the same for as long as you can imagine.

14. An Army of Workers Tried to Clean It Up

Firefighters and cleanup crews were dispatched to Chernobyl right away in an attempt to contain and clean up the disaster. Approximately 200,000 workers from all over the Soviet Union came to the site to clean up Chernobyl immediately following the disaster, in 1986 and 1987. It would take many more workers, and many more years, before the site was under control. A total of 600,000 people eventually worked at the site in order to get it cleaned up. An initial wave of 1,000 workers were hardest hit by doses of radiation during the clean up, but successive waves of cleanup crews experienced fewer ill effects of the disaster.

13. The Event Was Immediately Downplayed

Despite the massive fire, the radiative smoke and the resettlement of more than 100,000 people in the early phases of the Chernobyl event, the seriousness of the accident was immediately downplayed in the media. A statement was released by the Soviet Union only when the radiation alarms went off at a nuclear power plant in Sweden. That’s when the USSR told the public the following: “There has been an accident at the Chernobyl Nuclear Power Plant. One of the nuclear reactors was damaged. The effects of the accident are being remedied. Assistance has been provided to any affected people. An investigative commission has been set up.”

12. It Can Still Kill You

Though some people unofficially live within the exclusion zone, you can still die due to exposure around Chernobyl. It’s visited by tourists and it’s been photographed hundreds of times, which creates the false impression that it’s safe to be here. This is not the case. While things are definitely getting better, there are still radioactive hot spots in the area. Areas inside Pripyat and the nearby red forest will set off a Geiger counter, and that means people can still be exposed to harmful levels of radiation here. The red forest is so named because of the dead trees here, which turned a reddish color in the wake of the disaster. The forest is now a name only; the trees were bulldozed and buried.

11. Chernobyl Kept On Running

In spite of the disaster, the Chernobyl power plant wasn’t completely shut down for years. Many people don’t know that Chernobyl was still creating power in Russia until 2000. About $400 million was spent improving what remained of the power plant to fix the surviving reactors, making them much safer. One of them remained in operation until December 2000 and supported 6,000 workers every day. The doses of radiation they received have been deemed to be within acceptable limits. Even reactor 4 wasn’t close fully after the disaster. A very small team of scientists continued to work inside the destroyed reactor building for years after the event.

10. It Was Our Biggest Accident

The meltdown of Chernobyl created the largest uncontrolled release of radioactive materials into the environment of any civilian operation in history. It’s also the only accident in the history of commercial nuclear power that created fatalities due to radiation. It is only one of two level 7 events on the International Nuclear Event Scale, holding the dubious title with the awful Fukushima nuclear disaster of 2011. Chernobyl is known as the biggest nuclear disaster in history, and it is still used as a horrific example of everything that can go wrong when it comes to creating nuclear power. That’s why images of this event still resonate.

9. It Still Needs to Be Contained

There is a huge concrete shelter now around Chernobyl 4, where the reactor melted down. However, this barrier was very quickly put in place in 1986 and it is not viable for long term containment. Major work was done to the barrier in the late 1990s, but extensive work is still needed. A New Safe Confinement structure is scheduled to be completed this year. The project is ongoing. This new structure, made with metal, will cover all of Chernobyl 4 and the concrete shelter that’s currently around it. It’s scheduled to be finished in November 2017. The New Safe Confinement structure will continue to protect the world from the harmful radiation.

8. Plant Workers Were in Complete Denial

Though great measures were taken later to clean up and contain the site, initially the Chernobyl accident was an unmitigated disaster. The chief engineer stayed in the control room even as everything began to go wrong, seemingly in disbelief that a true nuclear disaster was unfolding before his eyes. He actually dispatched two men to lower the reactor rods even as black radioactive smoke was spilling out of the open roof, which had been blown off in the explosion. The two men died within a minute, and still workers remained at their stations. Many of them started to vomit from radiation sickness even as they continued to attempt to work. People who worked at the plant came to work that morning for their normal shift, and were told to expect to come in as normal the next day.

7. The Disaster Created Change

After the horrible accident at Chernobyl, nuclear power in the eastern hemisphere changed. The rest of the world, and Russia, learned a lot from that event. A nuclear renaissance, of sorts, followed the Chernobyl disaster. Reactor design improved greatly in this part of the world, and there was an increased focus on nuclear power safety after 1986. Many reactors were completely remodeled and redesigned to reflect new safety features, and new plans were put into place to better prepare for and deal with radioactive disasters. Chernobyl helped to make the rest of the world safer, though it took disaster for it to happen.

6. Thousands of People Have Died Too Early

How many people became ill as a result of Chernnobyl? It’s not possible to accurately estimate the total human cost of the Chernobyl disaster. The UN has hypothesized that 4,000 people died earlier than they would have under normal circumstances because of the event. However, Greenpeace has provided a much higher estimate. They’ve stated that the actual human toll of the Chernobyl disaster is 20 times higher than the UN estimate. Because of people suffering birth defects and cancer due to the radiation, the disaster will potentially affect hundreds of thousands of innocent people living near the area where reactor 4 exploded.

5. The Exclusion Zone is Bouncing Back

Wildlife has started to return to the exclusion zone around Chernobyl, though the cleanup is not estimated to be completed until 2065. The animals here do have some radiation exposure that causes some strange birth defects and side effects to the wildlife. Wolves, beaver, deer, lynx, boar, elk, bears and eagles all make their home here, and large populations of animals are thriving. They have the unique luxury of living in an area that’s almost completely devoid of humans, which makes the exclusion zone a unique sort of animal habitat. You can still see stunted trees growing on the scarred ground and other evidence that the world is not quite normal here, but there is promising hope for the future.

4. The Tragic Amusement Park of Pripyat

The sad tale of the Pripyat Amusement Park is too tragic for fiction. It was open for a single day, enjoyed only very briefly, and operated under the shadow of radioactive smoke the entire time. The unsuspecting residents of Pripyat, assured that everything at Chernobyl was totally normal, came to the opening of the park on April 27 for fun and enjoyment. They didn’t know, then, that a horrific disaster had happened just the day before. Everyone at the park that day was being exposed to lethal amounts of radiation, and they would all be removed from their town by bus the very next day. The amusement park, hardly enjoyed, sits today as a grim reminder of what could have been.

3. Chernobyl is a Tourist Attraction

Since 2011, Chernobyl is a tourist attraction. Once open only to scientists, today any visitor is allowed to come here and take a look around. In pop culture, Chernobyl is something of a ghost town. The images of the area around the plant are iconic and remain chilling to this day, which draws photogs and curiosity-seekers from around the globe to the site. Mainly, tourists come to see the abandoned town of Pripyat. This town, quickly left by residents who had no idea of what was going on, truly has a haunted look to it. The town has been taken over by wildlife and infrequent visitors who come to see the desolate-looking landscape.

2. It Won’t Be Safe for You, Ever

Don’t make any plans for Chernobyl yet. Despite thriving animal populations and plant life that’s attempting to make a valiant comeback, Chernobyl is not safe for humans and will not be in your lifetime or the lifetimes of your ancestors for a hundred generations. Because of the toxic, deadly radiation that was sent into the air here, the entire area around Chernobyl will not be safe for human habitation for the next 20,000 years — at minimum. Every single image of Chernobyl is a frightening reminder of the realities of radioactive fallout, and a horrible harbinger of what nuclear war might someday bring.

1. It Was Worse Than Both Atom Bombs…Combined

The amount of radiation released due to the Chernobyl disaster was 200 times higher than the radiation released by the atom bombs dropped on Nagasaki and Hiroshima during WWII — combined. Greenpeace estimates that around 5 million people continue to live within the contaminated area created by the reactor 4 explosion. You can still find radiation in the food, the water and the wood these residents consume every single day. Radioactive rain from the disaster fell in Europe, even as far away as Ireland. The radiation was so strong immediately after the disaster, one firefighter’s eyes changed from brown to blue.

Chernobyl continues to be a grim reminder that humans have already invented the ability to destroy themselves, and possibly the entire world.

Sources: telegraph.co.uk, greenpeace.org, livescience.com, untamedscience.com, rt.com