'In 1946, Soviet school children presented a two-feet wooden replica of the Great Seal of the United States to the American ambassador. He hung the seal at his residence. A bald wooden eagle, which was part of the seal, had been bugged. In 1952, an inspection revealed that the eagle contained a microphone and a passive resonant cavity that could be stimulated from an outside radio signal. The equipment had no power source or transmitter making it much harder to detect. The cavity had a metallic diaphragm that moved in unison with sound waves from a conversation in the room.'
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