It is almost 30 years since the Chernobyl disaster, a catastrophic nuclear accident at the Chernobyl nuclear power plant in Ukraine, then part of the USSR. On 26 April 1986 technicians at reactor number four of the nuclear power plant were conducting a systems test when there was a sudden power surge. The reactor's fuel elements broke, leading to a huge explosion and blowing off the reactor cap. This exposed the graphite covering the reactor to the air, and it ignited. The fire burned for nine days, sending a huge plume of radiation into the environment. It has been estimated that the Chernobyl disaster released into the atmosphere 400 times more radioactive material than the atomic bombing of Hiroshima in 1945.

The disaster killed 31 people almost immediately – almost all of them reactor staff and emergency workers. Between 30 and 50 emergency workers died shortly afterwards from acute radiation. The long-term effects are not yet known but a report suggested the eventual death toll could reach 4,000.

The town of Pripyat, just a few kilometres from Chernobyl, was built in the 1970s to house the plant's workers and their families. Around 50,000 people once lived here in apartment blocks on tree-lined streets. The town had 15 primary schools, five secondary schools and a technical college. There was a hospital, two sports stadiums and an amusement park. Today Pripyat is a ghost town, its streets overgrown, its apartment blocks lying derelict. Books and toys litter the schools and kindergarten, a reminder of how quickly they were evacuated. The rusting Ferris wheel that still dominates the town has been widely photographed, and has become a symbol of the world's worst nuclear disaster.

Chernobyl abandoned town
An aerial view of the now iconic Ferris wheel at a former amusement park in Pripyat, abandoned after Chernobyl and increasingly reclaimed by natureSean Gallup/Getty Images
Chernobyl abandoned town
Moss has invaded the dodgem cars that stand in the former amusement park in PripyatSean Gallup/Getty Images
Chernobyl abandoned town
The ticket booth for the Ferris wheel in Pripyat has long since stopped welcoming anyoneSean Gallup/Getty Images
Chernobyl abandoned town
An emblem of the hammer and sickle on a Ukrainian flag stands on top of an abandoned apartment building in PripyatSean Gallup/Getty Images
Chernobyl abandoned town
The former Chernobyl nuclear power plant, including destroyed reactor four, can be seen on the horizon from the abandoned city of Pripyat.Sean Gallup/Getty Images
Chernobyl abandoned town
Frozen in time: Schoolbooks lie on pupils' desks in a classroom at the abandoned School Number 3 in PripyatSean Gallup/Getty Images
Chernobyl abandoned town
Pupils' chairs and rotting floorboards are seen in an auditorium of the abandoned School Number 3 in PripyatSean Gallup/Getty Images
Chernobyl abandoned town
Dusty Cold War-era gas masks once common in the former Soviet Union lie strewn on the floor in a classroom of School Number 3 in PripyatSean Gallup/Getty Images
Chernobyl abandoned town
Dolls and stuffed animals lie abandoned in the Zlataya Ribka (Golden Little Fish) kindergarten in PripyatSean Gallup/Getty Images
Chernobyl abandoned town
Toys and children's chairs lie in the Zlataya Ribka (Golden Little Fish) kindergarten in PripyatSean Gallup/Getty Images
Chernobyl abandoned town
Books litter the floor outside the library of the former Energetika cultural centre in PripyatSean Gallup/Getty Images
Chernobyl abandoned town
Warped floorboards pile up on a basketball court under peeling walls at the abandoned public swimming poolSean Gallup/Getty Images
Chernobyl abandoned town
Diving boards stand over a debris-filled pool at the abandoned Lazurna public swimming facility in PripyatSean Gallup/Getty Images
Chernobyl abandoned town
A damaged sign hangs at the abandoned Lazurna public swimming pool in PripyatSean Gallup/Getty Images
Chernobyl abandoned town
A sign marks the entrance to the pharmacy at the abandoned city hospital in PripyatSean Gallup/Getty Images
Chernobyl abandoned town
Rusting shopping trolleys and debris litter the floor of an abandoned supermarket in PripyatSean Gallup/Getty Images
Chernobyl abandoned town
The abandoned Energetik cultural centre, which once housed a library, lecture halls and sports facilitiesSean Gallup/Getty Images
Chernobyl abandoned town
Murals decorate the crumbling interior of the abandoned Energetika cultural centre in PripyatSean Gallup/Getty Images
Chernobyl abandoned town
A rusting phone booth stands outside an abandoned furniture store in PripyatSean Gallup/Getty Images

The village of Kopachi, only a few kilometres south of the plant, had a population of 1,114. The village was so badly contaminated by radiation fallout that authorities bulldozed and buried all of Kopachi's homes and buildings, apart from the kindergarten. Today Kopachi, which lies in the inner exclusion zone around Chernobyl, is still contaminated with plutonium, cesium-137 and strontium-90.

Chernobyl abandoned town
Children's beds stand in the abandoned kindergarten in Kopachi, a village located inside the Chernobyl Exclusion ZoneSean Gallup/Getty Images
Chernobyl abandoned town
A doll lies on a child's bed at the abandoned kindergarten in the village of Kopachi that remains contaminated by radiationSean Gallup/Getty Images
Chernobyl abandoned town
Books and music notes lie strewn on the floor in the abandoned kindergarten in Kopachi, a village located inside the Chernobyl Exclusion ZoneSean Gallup/Getty Images

The former Chernobyl power plant is currently undergoing a decades-long decommissioning process of reactors one, two and three, which continued in operation for years following the accident at reactor four. A consortium of Western companies is building a movable enclosure called the New Safe Confinement that will cover the reactor remains and its fragile sarcophagus in order to prevent further contamination.

Chernobyl abandoned town
Workers sit in the control room of reactor number two that remains in operation to this day following the Chernobyl explosion that affected reactor fourSean Gallup/Getty Images
Chernobyl abandoned town
Dials in the control room of reactor number two; nearly identical to those in the control room of reactor fourSean Gallup/Getty Images
Chernobyl abandoned town
Instrument panels are seen in the control room of reactor number two that closely resemble those in reactor fourSean Gallup/Getty Images
Chernobyl abandoned town
An employee walks along a corridor near reactors one and two inside the former Chernobyl nuclear power plantSean Gallup/Getty Images
Chernobyl abandoned town
An emergency telephone stands in a corridor inside the Chernobyl nuclear power plantSean Gallup/Getty Images
Chernobyl abandoned town
A heavy metal door with a sign warning of radiation is fixed to the wall separating reactors three and four inside the former nuclear power plantSean Gallup/Getty Images
Chernobyl abandoned town
A visitor touring the former Chernobyl nuclear power plant takes a photo through a window looking towards facilities that house reactors one and twoSean Gallup/Getty Images
Chernobyl abandoned town
A worker walks at the New Safe Confinement construction site where the structure being built will one day cover the contaminated reactorSean Gallup/Getty Images

The Chernobyl Exclusion Zone was established soon after the disaster. All villages in a 30km (19 mile) radius of the plant were evacuated and placed under military control. The Exclusion Zone has since been widened and it now covers an area of 2,600 square kilometres (1,600 square miles). Today the Exclusion Zone is one of the most radioactively contaminated areas in the world, but radiation levels vary widely across the zone.

Chernobyl abandoned town
A sign warns of radiation in the recovering 'red forest' near the former Chernobyl nuclear power plant, so named because it was so heavily contaminated that trees turned redSean Gallup/Getty Images
Chernobyl abandoned town
A map at the Dityatki checkpoint shows the inner and outer zones of the Chernobyl Exclusion ZoneSean Gallup/Getty Images
Chernobyl abandoned town
An abandoned 140-metre-tall Soviet Cold War-era radar system known as The Woodpecker, used to detect incoming missiles, still stands inside the Chernobyl Exclusion ZoneSean Gallup/Getty Images
Chernobyl abandoned town
A house stands in Zalisya, a village that before 1986 had a population of approximately 3,000, about 15km south of ChernobylSean Gallup/Getty Images
Chernobyl abandoned town
A notebook, beer bottles and a plate lie on a flaking table in an abandoned house at Zalisya village, located inside the Chernobyl Exclusion ZoneSean Gallup/Getty Images

Nobody can say for sure when the area will be safe again, but some scientists estimate that it could be 20,000 years before people can live near the plant again. On an encouraging note, wildlife is thriving inside the Chernobyl Exclusion Zone, with elk, roe deer, red deer, wild boar, and wolves flourishing at the site of the world's worst nuclear disaster.