Today is the 39 -th anniversary of the day that was forever engraved in the history of mankind. On 26 April 1986, the world witnessed one of the largest man-made disasters - that of the explosion at the Unit 4 of the Chornobyl Nuclear Power Plant. On this day, the staff of the Chornobyl NPP held some memorial events to commemorate the liquidators` heroism, their courage and self-sacrifice for the safety of the whole world.