10 Insane Plans You Won't Believe The Military Tried
8. The CIA's Spy Cats

Sometimes, a top-secret military operation will have its true intentions hidden behind an opaque code-word for a title. Other times they're appallingly obvious and descriptive, and it's the latter case with the CIA's Acoustic Kitty project, which was implemented during the Cold War. And yes, it involved employing cats as listening devices.
The proposed plan from the CIA's Directorate of Science & Technology was that they could use felines to spy on the Kremlin and Soviet embassies, with the first Acoustic Kitty mission being to eavesdrop on two men in a park outside the Soviet compound in Washington. It didn't work out the released cat was immediately ran over by a car.
The technology behind Acoustic Kitty was flawless, at least, using a vet to stick a microphone in the cat's ear canal, a small radio transmitter at the base of its skull and a thin wire into its fur. Being ran over, distracted, or hungry were all problems the project failed to overcome before being cancelled in 1967 after $20 million had been spent on it.