Einstein visiting the observatory of Mount Wilson

German-born physicist Albert Einstein (1879-1955) visiting Mount Wilson Observatory, California, which at that time operated the world's biggest telescope, 1931. Among the group are American astronomers Edwin Hubble (1889 - 1953, back, second from left), Walter Sydney Adams (1876–1956, centre, in hat) and William Wallace Campbell (1862 -1938, far right) (Photo by Imagno/Getty Images) [Albert Einstein besucht in Amerika das Observatorium von Mount Wilson, welches zu dieser Zeit das groesste Teleskop der Welt betrieb. Photographie, 1931.]