Known as the "Chernobyl Three," engineers Alexei Ananenko, Valeri Bespalov, and Boris Baranov risked their lives to prevent an apocalyptic catastrophe just days after the historic explosion at the nuclear power plant in 1986.
Almost as soon as firefighters started pumping water into the reactor, it began flooding a basement room directly below. The basement contained the valves that controlled the coolant liquid that normally kept the reactor stable. But as the reactor rose to 2,000 degrees Fahrenheit, it began to melt the protective concrete floor below.
Experts feared that if the molten nuclear material came into contact with the water, it would unleash a gigantic steam explosion that would destroy the entire power plant, level Kyiv 60 miles away, and release so much radiation into the air that most of Eastern Europe would be uninhabitable for at least 100 years.
So on April 28, 1986, Ananenko, Bespalov, and Baranov volunteered to descend into the basement, locate the valves, and drain the tank. Protected only with diving suits and respirators while armed with a single flashlight, they waded through the radioactive water in near pitch-black darkness.
It took several days of many descents for them to find the valve and turn it enough to begin the draining process, and by May 8, a full 20,000 tons of water had been pumped out, sparing millions of lives from a nuclear winter.