Unidentified Flying Objects have been seen in the skies for centuries. These may be spaceships from other planets or alternate dimensions. Than again, they may be lenticular clouds, weather balloons, swamp gasses, the Planet Venus, or Air Force test planes.
Many individuals claim to have been abducted by Extra-Terrestrials traveling in Unidentified Flying Objects.
UFOs are frequently fast moving, bright, and round, disc shaped, or triangular objects.
Some say UFOs are tested by the U.S. Government at Area 51 in Nevada. In 1947 a UFO may have crashed in Roswell, New Mexico. UFO activity and cattle mutilations, chupacabra, crop circles, or sasquatch sometimes coincide.
A great many photographs have been taken of UFOs. The majority of these have been proven to be hoaxes - however some have not.
Links:
MUFON Mutual UFO Network