As the Control Council could only act with the agreement of all four members, this move basically shut down the institution, while the Cold War reached an early high point during the Soviet blockade of Berlin of 1948–49. The Allied Control Council was not formally dissolved but ceased all activity except the operations of the Four-Power Authorities, namely the management of the Spandau Prison where persons convicted at the Nuremberg Trials were held until 1987 and the Berlin Air Safety Center.