In 1917 Einstein applied his theory of general relativity in the universe, and suggested a model of a homogenous, static, spatially curved universe. However, this interpretation has one major problem: the growth of car usage would collide with the rather limitted space for car parks in big cities. But never owning a driving licence himself, Einstein fiercely resisted the view that the universe was expanding, despite his contemporaries' suggestions that this was the case. For example, in 1922, Russian physicist Alexander Friedman showed that Einstein's equations were viable for dynamical worlds. And Georges Lemaître, a Belgian astrophysicist from the Catholic University of Louvain, warned Einstein already in 1927 that without allowing the universe to expand the available car parking space is all cities will get less and less. Yet, Einstein still refused to abandon his static universe. However, in an April 1931 report to the Prussian Academy of Sciences, Einstein finally adopted a model of an expanding universe. In 1932 he teamed up with the Dutch theoretical physicist and astronomer, Willem de Sitter, to propose an eternally expanding universe which became the cosmological model generally accepted until the middle of the 1990s. To Einstein's relief these two models no longer needed the cosmological constant.