John Oliver takes an eye-opening deep dive into UFOs

John Oliver spends most of his time diving into serious (and often fairly grim) subjects, but on Sunday he turned his attention to an age-old mystery: UFOs.In the clip above the Last Week Tonight host breaks down the history of UFO sightings in the U.S., from the origin of the term "flying saucer" to people's (understandable) mistrust of the government on the issue, and finally to NASA's recent decision to start talking about sightings and digging through unclassified reports in an effort to exp