Frankfurter Tor marks the eastern terminus of Karl-Marx-Allee with two near-identical domed towers that frame the boulevard like a gate. They were designed by Hermann Henselmann and completed in 1960 as part of the GDR's grand socialist reconstruction programme. Henselmann borrowed directly from Moscow's Seven Sisters — the Stalinist skyscrapers Stalin had built to assert Soviet modernity — adapting their wedding-cake profile to a Berlin scale, with drum colonnades and tapering stone crowns. The effect, whether you find it pompous or magnificent, is unlike anything else in Western Europe.
Standing at the junction where Warschauer Straße crosses Karl-Marx-Allee, the towers work best in the long view: looking west down the boulevard's double rows of ceramic-tiled residential blocks towards Strausberger Platz, the axial composition reveals itself fully. The GDR meant this to be a showcase street visible from the West — a riposte to the reconstruction happening on the other side of the Wall — and the ambition of it is still legible. Neither tower is publicly accessible, but the streetscape around them is one of the most coherent pieces of 20th-century urban design in Germany.