Victor Gaydack is now in his 70s and lives in a Kiev suburb. In April 1986 he was a major in the Russian army, on duty when reactor four at Chernobyl exploded. He was one of tens of thousands of fit, young “liquidators” sent in from all over the Soviet Union to try to make safe the stricken reactor. Since the accident, Gaydack has suffered two heart attacks, and developed severe stomach cancer.

Who is to say that Gaydack’s conditions were not caused by the accident or would have happened without the explosion? Or that the many mentally disabled Belarussian children and the thousands of people born in the fallout region who today suffer from thyroid cancers and congenital diseases were not also Chernobyl victims? Estimates of the eventual deaths, cancers, heart diseases, ailments and malformations that will eventually result from the accident vary enormously and are still bitterly contested by scientists.

What is certain is that about 350,000 people like Gaydack were evacuated and resettled from the high-level 2,600 square kilometre contamination zone that stretches from Ukraine into Belarus and Russia. It is certain, too, that the accident cost tens of billions of dollars in today’s money and that the area around the plant will be psychologically cursed for hundreds, if not tens of thousands of years.

What has been less understood however is that Chernobyl changed the course of the world’s history and that its long shadow will hang over nuclear power for centuries. In an essay in National Geographic photographer Gerd Ludwig’s new book of the aftermath of the accident, Mikhail Gorbachev, the last president of the Soviet Union and on whose watch Chernobyl occurred, makes it clear - not for the first time - that the accident greatly accelerated the end of Soviet Union.

He writes:

The nuclear meltdown at Chernobyl even more than my launch of perestroika, was perhaps the real cause of the collapse of the Soviet Union five years later. Indeed, the Chernobyl catastrophe was an historic turning point: there was the era before the disaster, and there is the very different era that has followed … the Chernobyl disaster, more than anything else, opened the possibility of much greater freedom of expression, to the point that the system as we knew it could no longer continue. It made absolutely clear how important it was to continue the policy of glasnost.

There’s no photograph of Gorbachev, but there is one of Gaydack, in his flat watching, horrified, as the Fukushima disaster unfolds on television 26 years later. There are also plenty of heartbreaking images of children without limbs, dramatic shots of the physical disaster in the belly of the stricken reactor and the wild world that has been left beyond ground zero.

“It is virtually impossible to connect specific illnesses to particular causes, but there is no doubt that the families and the doctors who work with the sufferers in radiation hospitals and who are brave enough to speak out have good reason to blame the disaster,” says Ludwig, who has documented the world’s worst nuclear disaster in nine visits over 20 years.

“Women exposed to the fallout as children have now reached childbearing age and fear giving birth to babies with congenital defects, worrying how radiation may have affected their genes. While some in the scientific community question that birth defects and retardation are directly attributable to the disaster, noted scientist Alexei Okeanov [of the International Sakharov Environmental University in Minsk, Belarus] calls it ‘a fire that can’t be put out in our lifetimes’.”

Entombing the radiation, a brick wall blocks the entrance to the control room of reactor four, where the fatal mistake occurred. It created a safer passage for workers who have to walk through the area. After the Chernobyl nuclear accident, a concrete and steel encasement, the so-called sarcophagus, was hastily erected to contain the radioactive remnants inside the failed reactor. Only intended to be temporary, it is leaky and structurally unsound. Scientists agree that it will ultimately give way, shaking loose enough radioactivity to cause a second disaster of even greater magnitude.

The destructive effects of cesium to the thyroid gland are undisputed. The Chernobyl accident released severe fallout of cesium 127 that drifted north-west over Belarus, contaminating thousands of square miles of fertile land. The highest cesium concentrations are found in mushrooms and berries, and when ingested in large amounts over a prolonged period it accumulates in the thyroid gland, causing anomalies and cancers. Severe cases often require multiple thyroid surgeries to remove cancerous growths.

At the Thyroid Centre in Minsk, surgery is performed on a daily basis. Amongst the patients in room #4 was Dima Bogdanovich, 13, who had just undergone his first surgery for thyroid cancer, and liquidator Oleg Shapiro, 54. He was exposed to high doses of radiation while remanteling small wooden homes in the villages close to the reactor. His commission was originally for six months. Blood tests were administered after three months and the workers were mysteriously sent home. Oleg says that out of the 300 workers in his brigade, one-third have since died. He himself has already been through three thyroid operations.

Despite scientific dispute over the cause of physical malformations, many homes in Belarus receive support from Chernobyl aid programmes funded by various international aid organisations around the world. Activist Adi Roche, is an Irish woman who founded the organisation, Chernobyl Children, and produced the 2004 Academy Award-winning documentary on Chernobyl victims called Chernobyl Heart. Adi has made the care of Chernobyl victims the centre of her life. Her organisation gives major help to the children’s home in Vesnova, which cares for 150 abandoned and orphaned children with severe mental and physical disabilities. Some pictures show children with lesser disabilities harvesting fields and taking care of farm animals to produce food for the home.

When Soviet authorities finally ordered the evacuation, the residents’ hasty departure often meant leaving behind their most personal belongings. The Soviet Union only admitted to the world that an accident had occurred two days after the explosion, when the nuclear cloud reached Sweden and scientists there noticed contamination on their shoes before entering their own nuclear power plant.

Victor Gaydak, 70, liquidator of the Chernobyl accident, is watching the news from the nuclear disaster in Fukushima, Japan. A major in the military, he was on duty when the explosion occurred. Following the disaster he had two heart attacks, and developed severe stomach cancer. Evacuated from Pripyat, he now lives with his family in Troeschina, a suburb of Kiev, where more than 30% of the population are people relocated after the Chernobyl accident. An estimated 800,000 people, called liquidators participated in containing the Chernobyl disaster, cleaning up after the accident, and building the sarcophagus around the destroyed reactor. Most liquidators received high doses of radiation resulting in cancers and other diseases induced by their exposure, often only showing up decades after the event.

The empty school rooms in Prypyat- once the largest town in the zone with 49,000 inhabitants - are being taken over by nature.

On April 26, 1986, the nuclear accident at the Chernobyl Nuclear Power Plant in Ukraine contaminated thousands of square miles, forcing 150.000 inhabitants within a 30km zone to hastily abandon their homes. Nineteen years later, the still empty school and kindergarten rooms in Prypyat- once the largest town in the zone with 49.000 inhabitants bear witness to the sudden and tragic departure.