From UFOs over the Whitehouse to burnt Frenchmen and strange city-wide sightings, these are the 7 most credible UFO sightings. When most UFOs are spotted logical conclusions blame military aircraft for the incident, and discussions immediately turn to the Air Force covering up a test run of their new fancy-pants fighter jets. But when it's the Air Force themselves who witness such events, they know for sure that the strange unidentified craft they're looking at definitely isn't one of their own. Another common explanation for many UFO sightings is a mistakenly identified incoming meteor, but when the famous Green Fireball sightings of New Mexico were analysed by an expert, he concluded otherwise. In 1952 a number of UFO sightings were reported by many witnesses over Washington DC, and not only did members of the public and the Air Force take notice, but President Harry Truman also became involved in the investigation. Did you think it was just drunk-ass Americans who claim to encounter UFOs? Not so, because in 1976 over the skies of Tehran, Iran's capital, several Iranian pilots flying F-4 Phantom jets encountered a mysterious blue and red cylindrical object which disabled their aircraft's navigation and communication systems. The aircraft had been scrambled after the object was spotted by radar entering restricted airspace, and the Iranians weren't in the mood for messing around, so after seeing attempts at communication shut off the pilots decided to engage the craft aggressively. But as the Iranians prepared to fire upon the UFO their weapons systems were suddenly shut down. Trans-En-Provedence, South-Eastern France, January 8th 1981. 55 year old farmer Renato Nicolai hears a weird whistling noise whilst he's working, he turns round to see an eight-foot wide metallic double-stacked saucer land on his property and then shoot off into the sky again. Was Mr Nicolai on his fourth bottle of wine by this time? Perhaps, he is French after all, but in this eerie UFO incident there's one kind of credibility which no other entry on this list has - evidence. On October 4th 1967 at least eleven people saw a dimly-lit craft smash into the waters of Nova Scotia's Shag Harbour and float on the surface briefly, sinking before anyone could reach it. But after a thorough investigation which included local fishing boats, rescue co-ordinators and the Canadian military, no traces of a craft were found either on the water or at the bottom of Shag Harbour. A UFO sighting is a lot like an orgy - to have credibility it usually needs more than one person involved, two would be nice, five would be great, and ten would be spectacular. But in 1997 possibly one of the most credible UFO sightings ever occurred in Nevada and Arizona in March 1997, and it was witnessed by thousands.