Einstein Tower in Potsdam reopens after restoration

The Einstein Tower (Einsteinturm), a solar observatory built to test Albert Einstein's theory of relativity, has reopened in Potsdam, Germany, after a conservation restoration that began in 2021. Located 25 km southwest of Berlin in the Einstein Science Park, the 20-meter-tall tower was designed by architect Erich Mendelsohn in collaboration with astronomer Erwin Finlay-Freundlich and Einstein himself, built between 1919 and 1924. Its expressionist architecture, with no right angles, houses a system of mirrors and lenses directing sunlight from rooftop telescopes to a spectrograph and observation labs in the basement. Originally intended to be concrete, it was built in stuccoed brick due to post-WWI material shortages, causing structural issues from the start. Damage from WWII bombing was addressed in a late-1990s restoration. The latest restoration, costing about €1.25 million and 10,000 hours of labor, was supervised by engineer Hagen Mehmel, who called the tower "fantastic" but "a fiasco from a structural engineering perspective." The tower is still used for training students and testing instruments for larger solar telescopes. It will be open for guided tours only in winter months. The Leibniz Institute for Astrophysics has launched a digital exhibition, "Einsteinturm Revisited," commissioned by the Wüstenrot Foundation, which largely funded the restoration. German Science Minister Manja Schüle stated the tower remains a symbol of scientific excellence.