Acoustic Kitty was a CIA project launched by the Directorate of Science & Technology in the 1960s attempting to use cats in spy missions, intended to spy on the Kremlin and Soviet embassies, recording the links between the buildings in the area. A battery and a microphone were implanted into a cat and an antenna into its tail. This would allow the cats to innocuously record and transmit sound from its surroundings. Due to problems with distraction, the cat's sense of hunger had to be addressed in another operation. Surgical and training expenses are thought to have amounted to over $20 million.[citation needed]