By the late 1940s the U.S. government knew it had a problem on its hands. “Flying saucers” posed a threat to other aircraft, and possibly even the planet. So they created programs to study UFOs in secret, and stored the evidence in the highly classified Hangar 18. What do we know about their discoveries? And what exactly did they find in the Roswell wreckage? This is the third episode of our 75th Roswell anniversary special.