A solar observatory built to substantiate Albert Einstein’s theory of relativity has been reopened in Potsdam. Constructed between 1920 and 1922 by the architect Erich Mendelsohn in collaboration with the astronomer Erwin Finlay-Freundlich, the 20-metre tower, said at the time to resemble a “gawky spaceship”, has long been a lure for architectural enthusiasts and astrophysicists alike.

A digital exhibition has been launched to give more information to visitors, most of whom will only view the tower from the outside.

The Guardian: Observatory built to represent Einstein’s theory of relativity reopens in Germany