A dozen SIGSALY terminal installations were eventually set up all over the world. The first was installed in the Pentagon building rather than the White House, which had an extension line, as the US President Franklin Roosevelt knew of the British Prime Minister Winston Churchill's insistence that he be able to call at any time of the day or night. The second was installed below street level in the basement of Selfridges department store on Oxford Street, London, close to the US Embassy on Grosvenor Square. The first conference took place on 15 July 1943, and it was used by both General Dwight D. Eisenhower as the commander of SHAEF, and Churchill, before extensions were installed to the Embassy, 10 Downing Street and the Cabinet War Rooms. One was installed in a ship and followed General Douglas MacArthur during his South Pacific campaigns. In total during WW2, the system supported about 3,000 high-level telephone conferences.