The U2 platform opened on 1 October 1908 with the new U-Bahn section from Potsdamer Platz to Spittelmarkt. The station beneath the crossing of Friedrichstraße and Mohrenstraße was designed by Alfred Grenander and initially called FriedrichstraßeJ. Meyer-Kronthaler, Berlins U-Bahnhöfe, Berlin: be.bra, 1996. The second platform of the present-day U6 line was finished on 30 January 1923, but was built about southwards at the corner of Friedrichstraße and Leipziger Straße, the main east-west thoroughfare of the Friedrichstadt quarter. The platforms are connected by a pedestrian underpass colloquially called the Mäusetunnel ("mice tunnel"). The station received its current name in 1936.