Friedrichshain is the new Prinzlauerberg, which was the new Mitte. In the East everything is changing – even the ‘Plattenbau’. Literally meaning ‘plate-buildings’ these prefabricated soviet monsters are becoming sought-after. The beautiful lumps of Stalinist concrete that line Karl Marx Allee still house some of the original tenants. With a special key, though, the lift now goes up one more floor to the glass penthouses that have landed on the roof.