Cesium-137 is one of the numbers of the radioactive substances emitted in the environment during the disaster at the fourth power unit of the Chornobyl Nuclear Power Plant. In Latin Cesium means «sky-blue». Along with other hazardous substances, this azure dust contaminated the Exclusion Zone and resulted in thousands of destroyed lives. The authors of the documentary project Azure Dust managed to find two people with unique fate who lived in Prypyat at the time when the disaster happened.