In August 1945, a delegation from the Young Pioneer organization of the Soviet Union presented a carved wooden plaque of the Great Seal of the United States to U.S. Ambassador Averell Harriman, as a "gesture of friendship" to the USSR's World War II ally. 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.