During the height of the Cold War, two Siamese cats owned by Henri Helb, the Dutch Ambassador, began meowing, hissing and scratching at a specific wall of the ambassador’s study. Initially, the staff believed the cats were reacting to a potential mouse infestation, but after investigating the wall more closely they made a surprising discovery. Approximately 30 tiny microphones were hidden behind the paneling. It’s widely believed that the cats were able to detect the devices because they heard the high-frequency signals they emit, which are imperceptible to the human ear. Instead of openly confronting the Russians about the discovery and potentially revealing their counter-espionage methods, the embassy staff reportedly used the knowledge to their advantage by staging conversations with false or misleading information to feed their counterparts in the Soviet Union. The incident became one of the more unusual espionage stories of the Cold War, showcasing the unique high-frequency hearing abilities of cats.
