Die Glocke, or "The Bell" in English, was a series of projects and experiments conducted in Nazi Germany with the goal of achieving a large amount of goals, such as time travel, space travel, alien contact, superweapons, and others. The project began in 1937 on January 7 when Hitler began planning his invasion of Europe. Die Glocke didn't make much progress until September 3, 1941 when the construction of centrifuges was completed and April 10, 1941 when the first discovery of thermal diffusion and how to use it was made. Die Glocke was named after a central project with the same name that began at the same time, involving a large bell-shaped structure.