(April 26), a safety test at the Chernobyl Power Plant in Ukraine set off two explosions, triggering the world’s biggest nuclear disaster. However, it could have been worse had it not been for the heroism of three men — Alexei Ananenko,

Concrete crumbling like sand, their faces burning red from the radiation. Sky News speaks to Chernobyl workers who did everything they could to prevent a second explosion forty years ago.

Chernobyl is often described as the most expensive disaster in history, with an estimated cost of $180 billion (£133 billion) for Ukraine alone. By 2003, about 3.3 million Ukrainians were receiving benefits as Chernobyl “victims”.

Efrem Lukatsky, a Kyiv-based photographer for The Associated Press, was living in the city on April 26, 1986, when the explosion and fire struck the Chernobyl nuclear power plant, about a two-hour drive away.

On April 26, 1986, the Chernobyl nuclear reactor melted down, but the rest of the world wouldn't learn how close it came to nuclear Armageddon until weeks later.

For the past 40 years, the wastes of the Chernobyl site have stood as a monument to human arrogance, the danger of secrets, the plodding ineptitude of repressive regimes, and the catastrophes that occur when they all intersect.

In the weeks after the April 26, 1986, explosion and fire at the Chernobyl nuclear power plant, it was difficult to get any information about the scope of the disaster, aside from terse announcements from the government of the Soviet Union.

Photos of the infamous nuclear Chernobyl site show the abandoned power plant frozen in time — with a control panel still lit up ahead of the 40th anniversary of the unprecedented disaster.

Across the Chernobyl exclusion zone, Przewalski’s horses — stocky, sand-colored and almost toy-like in appearance — graze in a radioactive landscape larger than Luxembourg.