On 4 August 1945, a group of Russian children from the Vladimir Lenin All-Union Pioneer Organization, presented Averell Harriman, US ambassador to the Soviet Union, with a wooden replica of the Great Seal of the United States. Made from sandalwood, boxwood, sequoia, elephant palm, Persian ironwood, redwood, ebony and black alder, this gesture of friendship contained a hidden listening device. The gift was hung in the office of Harriman’s official residence in Moscow. Seven years later, it was discovered that the plaque was more than just a decoration and that the Soviets had been eavesdropping on Harriman and his successors the whole time, gathering crucial information about the post-war activities of the United States.
The ‘Thing’, as it was known, was the creation of Soviet inventor and physicist Léon Theramin, famous for inventing the musical instrument that bears his name. He designed the device while incarcerated in a secret research laboratory in a Gulag camp. Completely passive and requiring no power connection, the device was ingenious. It was designed to become active when remotely excited by radio waves of a certain frequency. Acoustic waves in the room where it was mounted caused it to vibrate and modulate the carrier radio wave. This modulation was then picked up by a separate device and converted back into audible speech allowing the Soviets to listen to conversations in the ambassador’s office from 800 m away in another building. The device was found when a US radio engineer discovered the presence of the powerful carrier wave by chance, launching a search for receiving devices.