The National UFO Reporting Centre reports 400 new UFO witness sightings every month. Disc-shaped objects, triangular craft and flying lights are the most common objects reported. Many believe UFOs come from outer space, but there's also another, more sinister, explanation. There is a new trail of evidence that leads back to secret Nazi technology and a post-war conspiracy to keep UFOs a mystery to this day. Indeed it is believed by many that UFOs got their start during World War II inside Hitler's Germany, and a new investigation reveals that Nazi engineers were working on disc-shaped craft, vertical take-off and advanced propulsion systems at this time. It is suspected that after the war, the US military secretly took the designs back to the United States, along with thousands of German scientists and engineers in order to continue with their ground-breaking developments. Many argue that it surely cannot simply be a coincidence that just two years later, in 1947, the first wave of UFO sightings occurred across the United States, and then around the world? Could UFOs be secret US aircraft, developed from captured German designs? To find an answer "Nazi UFO Conspiracy" looks at key evidence and some of history's most compelling UFO sightings to try and solve the mystery once and for all.