During World War II the Nazi's employed scientists to re-imagine the boundaries of scientific thought and practise. Many in the field of advanced weapon design - the programme that produced the V1 and V2 rockets that rained on Britain. But did this same unit produce rudimentary flying saucers? Declassified military documents detail the numerous reports by allied pilots of 'foo fighters', unusual craft with incredible acceleration engaging them in the skies above Germany. In addition there was the Nazi 'Der Glocke' or 'The Bell' project for a vertical take-off vehicle, which resembles eyewitness reports of a UFO crash in Pennsylvania after the war. Thousands of Nazi scientists were brought to the US at the end of the war. Are these men, and the projects they continued to work on in America, responsible to little green men, 400 UFO sightings a month and even the Holy Grail for ufologists, the Roswell incident?