During World War I the Berliner astronomer, Freundlich, plans the construction of a new telescope tower to measure the gravitational redshift. He asks the architect Erich Mendelsohn to design a building appropriate for the project. In the years following, Mendelsohn produces hundreds of design sketches and three plaster models. This third and the only surviving model is finished sometime in the summer of 1920, the same time as construction starts on the Telegraphenberg in Potsdam. It shows the Einstein Tower as it was actually built.