Alexei Wangenheim's area of expertise was clouds. Throughout the USSR, people relied on his forecasts to ensure that airplanes landed safely, ships found their way through the Arctic Ocean, and collective farms could harvest their crops on time. During the onset of the space conquest, his measuring instruments explored the stratosphere. He dreamed of harnessing wind and solar energy and believed in the future of socialism - even when he was arrested as a 'saboteur' for inexplicable reasons, and his life was thereafter devoted to death. During his years in the labor camp, he regularly sent letters to his young daughter Eleonora, containing picture puzzles as well as drawings of plants and animals. It was the discovery of this moving correspondence that led Olivier Rolin to follow in the footsteps of Alexei Wangenheim, the founder and first director of the Soviet weather service.