The fourth reactor of the nuclear power station in Chernobyl should have been disconnected for the purposes of periodic maintenance. It was decided to test the electronic system to see if it can keep the reactor´s cooling system running even if the power capacity is reduced. The experiment failed. The situation was made worse by the fact that the emergency cooling system had been disconnected, and the overheated system got even warmer. The initial explosion in Chernobyl was caused by the steam compressed in the cooling system, which was after a few seconds followed by a nuclear detonation. The blast killed two employees. After that, an enormous radioactive cloud , full of xenon and krypton gases, appeared. Firemen, who arrived at the site first, were hit by a lethal dose of radiation. Employees made great effort to extinguish a number of chemical fires. Soon after the blast the contaminated rain was falling down on southern Belarus. This area, along with the nearby Pripyat, was hit the most. The cooling system was directed straight in the Dnieper River, so consequently the water was also contaminated by the radiation.The Chernobyl tragedy was multiplied by the fact that the Soviet government did not provide information and kept everything secret. Cities near Chernobyl were evacuated two days after the explosion. The public did not have information about the exlosion for several days or nearly a week - until Swedish scientists have identified an radioactive cloud advancing north.
Southern and western sides of the former power station are surrounded with so-called Red Forest, which contributes to the terrifying impression of the landscape full of bare trees. Their trunks towers of thick layers of sand that was brought in order to isolate the surface radiation. Two concentric circles make a boundary of the prohibited zone at 10km and 30 km distance from the power station. The landscape is desolated and the villages are abandoned.