by Wolf Wertheim, who in 1909 opened a new department store, which operated until 1914. The building was auctioned off shortly before World War I. It is unclear how the building was used between 1914 and 1924. In 1924, among other additions to the building, a deep cellar was built. This cellar still exists today and is also known as the Tresorraum. The height of the ceiling in the passage was lowered to that of the stores, which changed the appearance of the building completely. Haus der Technik After 1928 the building was used as a show room by the Allgemeine Elektrizitäts-Gesellschaft (General Electric Company). It was renamed Haus der Technik by the proprietor, the Berliner Commerz- und Privatbank. The AEG used the space to display products and advise customers. The former AEG show room, located at Luisenstraße 35, had been destroyed by a fire on September 15, 1927. The new space covered over 113,000 sq ft (10,500 sq. meters) and used 20 large display cases. One of the first German television transmissions took place here during the 1930s. Use by the NSDAP In the early 1930s, the building was increasingly used by the National Socialist German Workers' Party (Nazi) party members. In the mid-1930s, the German Workers Front established offices for Gau Kurmark and became owners of the building in 1941. At the same time it became the central office for the SS. In 1943 the skylights were closed and the corresponding ridge turrets removed, so that French war prisoners could be held in the attic. During the Battle of Berlin the second cellar was flooded by the Nazis and remains underwater today. The building was heavily damaged during World War II, though a large portion of it survived intact. Use in the GDR In 1948 the building was taken over by the Free German Trade Union Federation (FDGB) and deteriorated over the course of the next several years. Various retailers and craft businesses temporarily moved into the ruins, especially on the Friedrichstraße side. The German Travel Agency used the repaired passage section and several floors above ground. Among others, there was an artists' school, a technical school for foreign trade and economics, and office spaces for RFT (Rundfunk- und Fernmelde-Technik), a company dealing with radio and transmission technology. The cellar was used by the National People's Army. The movie theater Camera was located in the Friedrichstraße gateway area,