October 1986: To mark the end of the clean-up operation atop reactor 3, the authorities ordered three men to attach a red flag to the summit of the chimney. A group of liquidators had already made two fruitless attempts by helicopter, so the three men had to climb the 78 metre chimney via a spiral staircase, despite the dangerous radiation levels. Radiation expert Alexander Yourtchenko carried the pole, followed by Valéri Starodoumov with the flag, while lieutenant-colonel Alexander Sotnikov ascended with the radio. The whole operation was timed to last only 9 minutes given the high radiation levels. At then end, the trio were rewarded with a bottle of Pepsi (a luxury in 1986) and a day off

Photograph: Igor Kostin/Corbis