 Unbeknown to anybody in the Embassy, it contained The Thing, a covert listening device (or "bug"), enabling the Soviet Union to spy on the United States.It hung in the ambassador's residential study undetected until it was exposed in 1952.From March to April 1947, Spaso House was the site of a meeting of the Council of Foreign Ministers, including Secretary of State George Marshall, who met in Moscow to draft the final peace treaties with Germany and Austria.