What is often claimed to be the earliest picture of a UFO, this picture was taken from the summit of Mount Washington, New Hampshire, in 1870
One of the earliest photographs of an unidentified flying object, this picture was taken somewhere in the United States during the 1920s
An object hovers over the sawmill in Ward, Colorado, in April 1929
New Year's Day in 1939: an unidentified man pictured somewhere in the US with an unidentified object in the background
So-called foo fighters were often pictured alongside Allied aircraft during sorties and raids in the Second World War
Searchlights converge on an unidentified object over Los Angeles on February 25, 1942. The bright blobs around the flashes are anti-aircraft shells exploding
This UFO was snapped by an American photographer in Tiensten, Hopeh province, China, in 1942. Several people in the photograph appear to be pointing up at the object
A Japanese Sally Bomber flies over the Japanese Sea in 1943 followed by a dark sphere
A famous picture taken in Burbank, California, in 1945 featuring Jack LeMonde on a horse with an object in the background
Three Army Air Force veterans reported six flying discs over Catalan Island, California, in 1947 and former aerial photographer Bob Jung said he succeeded in photographing one of the objects. The masts of a steamer can be seen at the bottom of the picture
This cylindrical-appearing UFO was photographed over New York City on March 20, 1950
Guy B. Marquand, Jr., took this picture on a mountain road near Riverside, California, on November 23, 1951. He said the object above the skyline was a "flying saucer"
An amateur photograph of a UFO taken in Passoria, New Jersey, in July 1952
On July 19, 1952, customs inspector Domingo Troncoso took this picture on the jungle frontier between Peru and Bolivia. The big dirigible-shaped craft was flying horizontally and fairly low in the sky, passing from right to left from the observer's posit
Washington DC 1952 and some UFOs were photographed flying over the Capitol building during a wave of sightings above the city
Four Sicilian men watch two unidentified objects over Sicily on December 10, 1954
Ella Louise Fortune, who worked as a nurse at the Mescalero Indian Reservation near Three Rivers, New Mexico, took this picture while driving along Highway 54 on October 16, 1957, near Holloman Air Force base
In September 1957 this picture was taken by a test pilot near Edwards Air Force Base in California. It shows a UFO apparently following a B-47 jet
This shot taken on January 16, 1958, over Trindade Island, Brazil, was widely dismissed as a hoax although doubts have now been expressed at this conclusion.
One of the many UFO photographs taken in Japan. This one shows an object over Kaizuka in 1958.
This picture was taken by an unidentified photographer on December 22, 1958, in Poland
In this picture by Trevor Constable taken on May 17, 1958, at Giant Rock, California, the object above the ridge was not seen by witnesses at the time but only became apparent after the film was developed
Another of the most famous UFO photographs ever taken, this was shot by Joseph Sigel on June 18, 1959 in Waikiki, Hawaii
This was taken on July 3, 1960, by Argentinian air force captain Hugo Niotti near Cordoba, Argentina
This picture was taken somewhere in the United States on June 10, 1964, and was discovered in an attic some years later
Alan Smith, 14, took this photograph at about 1.45am on Aug 2, 1965 from his back yard in Tulsa, Oklahoma. Five other witnesses saw the UFO change color from white to red to blue-green.
This object was photographed over Adelaide, Australia, in 1965. It was seen to hover for 20 minutes, then it shot off to the east.
Rex Heflin, an Orange County highway inspector, was at work in a county vehicle on August 3, 1965 when he saw a hat-shaped object hovering above the road. He grabbed his Polaroid camera and took three photographs of the metallic-appearing object
In the summer of 1966, a flight security official photographed two red spheres over the Swiss airport Zurich-Kloten. The photo was later released by Swiss Air pilot Ferdinand Schmid.