From November 20, 1945, until October 1, 1946, the International Military Tribunal (IMT) convened in the principal courtroom for criminal cases (room No. 600) in the Nuremberg Palace of Justice. At the conferences in Moscow (1943), Teheran (1943), Jalta (1945) and Potsdam (1945), the Big Three powers (USA, USSR and Great Britain) had agreed to try and to punish those responsible for war-crimes. Designated by President Harry S. Truman as U.S. representative and chief counsel at the IMT Supreme Court Justice Robert H. Jackson planned and organized the trial procedure and served as Chief Prosecutor for the USA. He recommended Nuremberg as site for the trials for several reasons. The Palace of Justice was spacious - it had 22,000 m2 of space with about 530 offices and about 80 courtrooms; war damage to it was minimal; and a large, undestroyed prison was part of the complex. The prosecution entered indictments against 24 "major war criminals" and against 6 "criminal organizations": Hitler's Cabinet, the leadership corps of the Nazi party, the SS (party police) and SD (security police), the Gestapo, the SA and the General Staff and High Command of the army.