Some of the most iconic UFO sightings have been spotted in the US - with many of the bizarre objects even convincing the government.
Unidentified flying objects have been spotted in the states for decades and many of them have been reported by US fighter pilots who reported seeing them while on duty.
One pilot, who was asked to monitor the strange objects in the sky, even failed to return after mysteriously disappearing.
And a former US Air Force captain recently revealed a "UFO attack left guards screaming" when the flying object came towards him in 1967.
Robert Salas headed a Malmstrom base in Montana, US, in 1967, when a guard came towards him and claimed "strange lights" were heading in their direction.
Charming UK village is 'UFO hotspot' with 'NASA scientists showing interest'He said they were "hovering motionless and without sound, and there was a solid object within the light that was oval-shaped."
The guard was stunned after witnessing the alleged UFO attack with the official left screaming amid concerns over a potential security risk.
He revealed the terrifying incident led to an investigation by the US Air Force.
Washington National Airport Sightings
The July, 1942 sighting came after the radar at Air Routing and Traffic Control Centre in Washington identified seven moving targets - all faster than any aircraft that existed at that time.
The radar scope indicated the objects were 15 miles south-southwest of Washington, DC, according to Air Traffic Controller Edward Nugent.
In addition, Washington's National Airport's control tower radar spotted several unidentified blips - with two of the controllers seeing a bright light moving at lightning speeds.
Four white glows travelling at 1,000ft were too fast for the pilots to chase.
They reported the scary incident to the US Air Force to investigate but it was later revealed the radar blips had been caused by temperature inversions.
The flying saucer over Alaska
Residents in Fairbanks, Alaska were left baffled in 1997 when a 300ft saucer, which appeared bigger than a planet, remained visible throughout a summer evening.
The incident sparked concerned calls from locals who were concerned a UFO was heading its way to them.
Top 10 most popular paranormal beliefs - including ghosts, aliens, and witchesHowever, it was quickly revealed, NASA was using a balloon to collect data about the concentration and weight of the stratospheric gases at sunrise.
The Observations of the Middle Stratosphere (OMS) balloon was carrying 1,700lb gondola housing scientific instruments, which were mistaken for a UFO, by locals.
Violently moving saucers and red lights
Captain Ruppelt, who led the US Air Force's Project Blue Book UFO-hunting project, was asked to investigate red lights in the sky in 1952.
Despite the best efforts of locals, residents across the country could not identify the object and, therefore, an F-94 pilot was sent to check out the strange bright red lights.
The pilot found a cluster of three Skyhook balloons and violently moving "saucers" were being reported.
According to reports, staff at the airfield refused to entertain the idea were balloons despite a CIA briefing paper declaring they were.
Staff in the report said the sighting "must have been of some other unknown origin."
Unexplained death of pilot
The death of Captain Thomas Mantell in 1958 was one of the most bizarre outcomes of a UFO search.
A mysterious flying object had been spotted by control tower operators at Godman Air Force Base in Kentucky.
The pilot was ordered to investigate the sighting in his P-51 Mustang and claimed it was a "metallic object."
He wrote in his report: "It appears to be a metallic object or possibly the reflection of the sun from a metallic object, and it is of tremendous size."
Mr Mantell informed operators he was flying higher in order to get a better look at the object - but then stopped communicating.
His aircraft wreckage was discovered near Franklin, Kentucky and his death remains a mystery still.
Experts believe his death was related to a Skyhook balloon, which was developed by the US Navy and is 20ft wide.
They were used for meteorological observations at high altitudes and officials believe he passed out as his aircraft climbed higher and was unable to prevent the plane crashing into the balloon.
Encountering a white orb for 27 minutes
A World War II veteran pilot encountered a white orb above Fargo, North Dakota for an astonishing 27 minutes in 1948.
George F Gorman reported the incident to the US government which attempted to analyse and document the early UFO sightings.
Mr Gorman, 25, who was flying a P-51 Mustang, told a local newspaper: "I've never seen anything like it. If anyone else had reported such a thing I would have thought they were crazy."
He initially thought it was the tail lights of another aircraft but when he tried crashing into it it managed to escape him - speeding off at a remarkable 600mph.
He said: "Once, when the object was coming head on, I held my plane pointed right at it.
"The object came so close that I involuntarily ducked my head because I thought a crash was inevitable. But the object zoomed over my head."
Officials believe it was a metrological balloon - despite two pilots backing up his story.