During WWII, American, British, German and French fighter pilots all reported seeing large glowing orbs in the sky that could not be explained - these came to be known as "foo fighters." The genesis of the name itself is unknown, but some have theorized it comes from the German word for fire "feuer." By Jessica Ferri.
2. Hopeh Incident, China
This photograph was taken in 1942 and later discovered in a photo album. The owner of the album claimed to have purchased the photograph from a street photographer in China. Some claim the UFO looks like a hat or a bird, others say it's a flying saucer.
3. Men In Black
In 1947, a seaman claimed to have seen six doughnut shaped UFOs flying in the air above Maury Island off the Puget Sound in Washington. One of the objects dropped debris on the deck, injuring his son and killing his dog. The next morning, the seaman claimed a man dressed in black and driving a black Buick showed up at his doorstep and made vague threats that his family would be in danger if he ever spoke to anyone about the incident.
4. First Flying Saucer Sighting
Just a few days after the Men in Black incident, Kenneth Arnold reported seeing nine UFOs flying in the air near Mt. Ranier, Washington. The press coined the term "flying saucer" to describe the objects, which stuck. Arnold stood by his story and became a semi-celebrity in the world of the paranormal.
5. Disappearance of Felix Moncla
While pursuing a UFO over Lake Superior in 1953, U.S. Air Force Pilot Felix Moncla disappeared into thin air. Ground control had both Moncla and the UFO on radar, and witnesses claimed the two blips "merged, then vanished."
5. Disappearance of Felix Moncla (Cont'd)
In 1968, parts from an aircraft where found in the lake, but were never confirmed as part of Moncla's aircraft.
6. Kecksburg Incident
On the night of December 9, 1965, residents of Kecksburg, Pennsylvania claimed something large crashed in the woods—an acorn shaped object with hieroglyphics written on the sides. The military quickly surrounded the area. In 2005, NASA explained that the falling object (recreated above) may have been debris from a Russian satellite, but witnesses claim that explanation is not consistent with what they saw.
7. Jimmy Carter's UFO Sighting
President Jimmy Carter described seeing a bright white object which then changed color from blue, to red, back to white before receding into the distance in Leary, Georgia, in 1969. Though he later claimed he never thought the object was an alien spacecraft, he said, "One thing's for sure, I'll never make fun of people who say they've seen unidentified objects in the sky."
7. Jimmy Carter's UFO Sighting (Cont'd)
"If I become President," Carter said in 1976, "I'll make every piece of information this country has about UFO sightings available to the public and the scientists."
8. The Grimming Man
Though The Grinning Man was first spotted after a UFO sighting in 1966 in Elizabeth, New Jersey, he has popped up all over the United States after other sightings, telling witnesses his name is "Indrid Cold." Witnesses have described him as a tall man who looks human, but has no nose or ears—only eyes and a large grin.
9. O'Hare Airport
On Tuesday, November 7, 2006, the FAA received reports that 12 airline employees at Chicago's O'Hare had spotted a metal saucer shaped craft hovering over one of the departure gates. According to witnesses, the disc hovered for about two minutes, but when people went out to investigate, it abruptly took off through the clouds. The FAA concluded that it must have been the weather playing tricks on people's eyes, but witnesses continue to insist that it was a UFO.
A night guard in Turkey named Yalcin Yalman witnessed a large amount of UFOs while on duty in 2008 and decided to tape them. He provided the Sirius UFO Space Research Center with two and a half hours of footage, prompting them to call the tapes, "the most important UFO images ever," though their veracity has yet to be proven.