1. Roswell, 1947
Ranking as one of the most famous UFO incidents in history - and now a pop culture phenomenon - the Roswell incident saw UFO hunters claim that the US military had captured an alien aircraft. While the military maintain that the 'flying saucer' was actually a surveillance device from a classified operation, non-believers still cite extra-terrestrial activity to this day.
2. Kenneth Arnold case, 1947
Newspapers had a field day with Kenneth Arnold's story, even coining the term 'flying saucer', after the American businessman and pilot claimed he'd seen nine saucer-like objects flying in a chain near Mount Rainier in Washington.
3. Washington, D.C. sighting, 1952
The CIA Robertson Panel was formed after reports of UFOs appearing in the skies above Washington were convincingly backed up by mysterious radar contacts at three separate airports. However, the US Air Force allayed fears of an alien invasion, suggesting that changes in the temperature had caused radar signals to bend and give false returns.
4. The Hill Abduction, 1961
In 1961, Barney and Betty Hill from Portsmouth, New Hampshire, reported that they had been kidnapped by aliens. According to the couple, they had been followed by a flying saucer while driving in their car, abducted and then subjected to an intimate physical examination. They also recall observing a 3D 'star map' inside the ship. Even under hypnosis, the Hill's maintained their story and aroused massive interest and publicity.
5. Rendlesham Forest Lights, 1980
One of the UK's most famous UFO events involved the sighting of several unexplained lights near RAF bases at Rendlesham Forest, inland of the Suffolk coast. The authorities insist there was nothing mysterious going on and no risk to national security, however, as the witnesses were on-duty servicemen, the reports were given a measure of credibility, and a belief persists that the lights were from an alien spacecraft. Even now, requests for more details are still being made under the Freedom of Information Act.
6. Clyde W Tombaugh sighting, 1949
Respected American astronomer Clyde W Tombaugh poured cold water on the consensus that most UFO sightings were recorded by publicity-seekers, when, two years after Roswell, Tombaugh recorded seeing up to eight rectangular lights in the sky above Las Cruces in New Mexico, and on another occasion several green fireballs. As a serious-minded astronomer used to studying the skies (one of his greatest achievements was the discovery of the dwarf planet Pluto in 1930), his inability to explain the lights made his claims particularly hard to dismiss.
7. Levelland case, 1957
Drivers in Levelland, Texas reported that their car engines stalled when encountering a glowing, egg-shaped object, and then mysteriously restarted again after the object had left. A police investigation followed and it was concluded that an electrical storm had caused the sightings and vehicle failures.
8. Shag Harbour, 1967
The navy was drafted in after a large, unidentified object crashed into Shag Harbour in Nova Scotia. A search and investigation was conducted, but later classified as unsolved by the Canadian Department of National Defence when a clear conclusion could not be reached.
9. Maury Island incident, 1947
Sailor Harold Dahl experienced a run-in with the real 'men in black', after claiming to have seen six UFOs while scavenging for driftwood in Washington's Puget Sound. The next day he was approached by an unknown, black-suited individual who warned him off repeating his story with threats against his family. However, it's unclear whether the UFO incident was actually real or a secret military exercise which had gone wrong.
10. Westall encounter, 1966
A UFO was allegedly witnessed by more than 200 students and teachers at two schools in Westall, Melbourne. The object was spotted first descending into a grassy field before taking off over houses in a local suburb. While Australian Skeptics, a non-profit organisation which investigates paranormal and pseudo-scientific claims by using scientific methodologies, put the UFO down to being an experimental military aircraft, witnesses contunue to gather to relive the extraordinary event.
11. Lonnie Zamora UFO sighting, 1964
When New Mexico traffic policeman Lonnie Zamora saw a huge, bluish-orange flame in the sky south of Socorro, he went to investigate. The flame was accompanied by a deafening roaring sound, and as Zamora drew nearer he saw a weird, doughnut-shaped silver machine and two white-clad individuals. Although the pair quickly flew off, Zamora's detailed testimony has provided one of the most comprehensive accounts of an alien encounter, and is often cited as a significant spur in persuading the US Air Force to take the growing numbers of UFO sightings more seriously.
12. Carson Sink incident, 1952
Two senior military pilots claimed to have spotted three aircraft of a type unknown to them while flying in a North American B-25 Mitchell bomber over the Carson Desert. They said the three unidentified objects were moving about three times faster than their B-25. While the B-25 wasn't known to be a particularly fast machine, both men insisted that the three crafts were not a new type of super-fast jet. 60 years later the sighting is still officially classified as unexplained.
13. São Paulo sighting, 1986
Military aircraft were sent to intercept around 20 UFOs detected by radar in various parts of São Paulo, Brazil. However, once the military began to give chase, the mysterious objects reportedly disappeared. Providing one solution to the incident is Geoffrey Perry, a British space researcher. He put the sighting down to debris that were ejected by Soviet space station Salyut-7 re-entering the Earth’s atmosphere around central-western Brazil.
14. Jimmy Carter sighting, 1969
Before becoming president of the USA, Jimmy Carter filed an official report in 1973 to say that four years earlier he had seen a strange white light in the evening sky. He claimed he watched it change from white to blue, and then to red, before changing back to white and appearing to gradually fade off into the distance. Although he believed it was a UFO he saw in 1969, by the time he became president he put the incident down to military, rather than extra-terrestrial, activity.
15. Teheran UFO incident, 1976
A UFO was believed to have disabled the electronic equipment of two F-4 interceptor jets as well as ground control equipment in Teheran. Public records state that the Iranian generals involved said that they had thought the object was an extra-terrestrial, although sceptics have put the encounter down to equipment malfunction.
16. Lubbock Lights, 1951
Three professors from Texas Technical College spotted an unusual light formation flying over Lubbock, Texas in 1951. The 20 to 30 lights flew in a 'V' shape over the town, and the occurance was eventually photographed by a student from the college with the photographs later appearing in Life Magazine, although an explanation of the sightings is yet to be found.
17. Belguim Wave, 1989 - 1990
Between 1989 and 1990, around 13,500 people claim to have observed large, silent, low-flying black triangles in the skies above Belgium, with 2,600 written statements on file about what they had seen. The frequently-photographed wave was also tracked by NATO radar and jet interceptors and investigated by Belgium’s military, although some put the sightings down to ordinary helicopters.
18. Yeni Kent Compound, 2008
One plucky night guard at the Yeni Kent Compound in Turkey claimed to have videotaped a number of UFO sightings witnessed over a period of four months. His allegations were also backed up by other witnesses, spurring the Sirius UFO Space Science Research Center to say that the videos were the “most important images of a UFO ever filmed”.
19. Berwyn Mountains, 1974
Like the Roswell incident 27 years earlier, rumours of a UFO crash in the Berwyn mountains followed after reports of shaking ground and strange lights in the sky. Investigations began and Gwynedd police recorded a statement from a witness who claimed to have seen a "bright red light, like coal fire red. Large perfect circle. Like a big bonfire. Could see lights above and to the right and white lights moving to bottom. Light changed colour to yellowish white and back again." No remains were found and the unsteady ground was likely to have been caused by the Bala Earthquake which hit the area that night, but several locals still insist they saw a glowing, egg-shaped craft.
20. Captain William Schaffner incident, 1970
When radar picked up an unidentified flying object over the North Sea, pilots quickly attempted to make contact. Captain William Schaffner intercepted a 'conical object' then all contact with him was lost. Three months later his plane was discovered undamaged on the seabed, but his body was never recovered. However, official reports eschewed the idea of an extra-terrestrial mystery, deeming the pilot's likely death being caused by flying too low over the sea
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