Einstein Tower

The Einstein Tower rises among the trees of the Telegrafenberg in Potsdam like something poured rather than built: a smooth, rounded shaft with deep-set windows, flowing down into a low body that seems to lean forward on its haunches. It was designed by Erich Mendelsohn, then at the start of his career, and it became the best-known work of his career and one of the landmarks of German Expressionist architecture. A young Richard Neutra worked in his office at the time.

Behind the sculptural shell is a precise instrument. The tower was built between 1919 and 1921 and began work in 1924 as a solar observatory for the astronomer Erwin Finlay-Freundlich, who wanted to test a prediction of Albert Einstein's general relativity: that the sun's gravity should shift the lines of its spectrum very slightly towards the red. Modelled on the tower telescope at Mount Wilson in California, it uses a coelostat — a pair of moving mirrors under the dome — to send sunlight straight down the shaft to a 60-centimetre lens, and from there into a long, insulated spectrograph laboratory set into the ground behind. That horizontal wing is what gives the building its stretched, animal profile. The effect Freundlich sought proved far harder to measure than expected, obscured by turbulence on the sun's surface, and was only confirmed in the 1950s; the tower turned instead to solar physics, and it remains a working observatory of the Leibniz Institute for Astrophysics Potsdam, today focused on solar magnetic fields.

Mendelsohn imagined the building in concrete, but wartime shortages meant much of it was built in brick and coated with render, and it has fought cracks and damp ever since — repairs began within five years, and a full restoration was completed in 1999. Einstein, who supported the project but never worked there, is said to have toured it in silence and later summed it up in one word: "organic". After 1933 the Nazis stripped the institute of his name; staff hid his bronze bust behind crates in the laboratory, and it now stands in the entrance. The grounds of the Albert Einstein Science Park are open by day and the tower can be admired from outside; the interior is shown only on guided tours, usually run by Urania Potsdam.

Getting there

The Telegrafenberg is on the southern edge of central Potsdam, about 2 km from the city centre. The nearest airport is Berlin Brandenburg Airport (BER), about 30 km away. Potsdam Hauptbahnhof, with regional and S-Bahn trains from Berlin, is the nearest main station.