Three boys await the arrival of Unidentified Flying Object (UFO) hunter Kim Carlsberg of UFO Sky Tours to begin their search outside Sedona, Arizona, as darkness falls in the desert on March 1, 2013. Mike Blake/Reuters
A UFO convention attendee dressed as an alien waves at a Roswell Police Officer directing traffic near the Roswell Convention Center, July 4, 1997. Roswell, the site of an alleged UFO crash in 1947, hosted an international UFO convention to mark the 50th anniversary of the incident. David Ake/Reuters
An unidentified object flies over Mexico City, seen through a very long telephoto lens, July 12, 2000. Mexico City residents rushed into the street today to observe the bright objects as they hovered over the city. TV stations showed the objects were in fact probably silvery helium filled balloons. Henry Romero/Reuters
Mexico City residents stop in their tracks to look up at unidentified objects flying over the capital, July 12, 2000. Heriberto Rodriguez/Reuters
People dressed in alien costumes pose for a photo in front of Pic de Bugarach mountain at a small party in the town of Bugarach, France, December 21, 2012. Although the long expected end of the Mayan calendar has come, the New Age enthusiasts have steered clear from the sleepy French town of Bugarach, which gave some locals a chance to joke about the UFO legends that surround the area. Marko Drobnjakovic/AP
Cosplayer Lorenzo Ramirez poses in his 'Free Face Hugger' costume, inspired by the face huggers from the 'Alien' movies, during the 2013 San Diego Comic-Con (SDCC) International in San Diego, California July 18, 2013. Fred Greaves/Reuters
This 1950 document released by the FBI under the Freedom of Information and Privacy Acts Section, shows a Federal Bureau of Investigation report of 'flying saucers' in New Mexico sent to then-Director J. Edgar Hoover in 1950. The document has become the FBI's most popular file in the bureau's electronic reading room. FBI/AP
Contestants ready to take the stage during the 2013 UFO Festival Alien Costume contest in Roswell, New Mexico on July 6, 2013. Mark Wilson/Roswell Daily Record/AP
An alien figure in a spaceship is seen in front of a hotel in the city of Alto Paraiso de Goias, central Brazil, December 20, 2012. Some residents believe that December 21, which is the last day of the Maya Long Calendar, will mark the end of the world. Alto Paraiso de Goias is considered a mystical city and has attracted many tourists, which according to local media, feel safe spending the fateful day there. Ueslei Marcelino/Reuters
'Nanook the Superdog,' right, and 'Tobie the King of Mars,' wait to take the stage during the Alien Pet Costume Contest portion of the 2013 UFO Festival in Roswell, New Mexico on July 6, 2013. Mark Wilson/Roswell Daily Record/AP
UFO sightings weren't mentioned in the CIA admission that Area 51 exists. The 407-page CIA document still contains many redactions, and, say UFO buffs, who's to say those missing sections don't involve UFO sightings?
ByHannah Dreier, Associated Press
UFO buffs and believers in space aliens are celebrating the CIA's clearest acknowledgement yet of the existence of Area 51, the top-secret Cold War test site that has been the subject of elaborate conspiracy theories for decades.