Theremin invented another listening device called The Thing. Disguised in a replica of the Great Seal of the United States carved in wood, in 1945 Soviet school children presented the concealed bug to U.S. Ambassador as a "gesture of friendship" to the USSR's World War II ally. It hung in the ambassador’s residential office in Moscow and intercepted confidential conversations there during the first seven years of the Cold War, until it was accidentally discovered in 1952.[30]