In honor of World UFO Day, here's a look back at one of Cheyenne's most infamous encounters. In the fall of 1988, a Cheyenne Police officer reported a mysterious aircraft hovering over the Capital City.

The officer told 911 dispatchers he saw a circular object with red, white, and blue lights moving slowly across the horizon. Other eyewitnesses also reported similar sightings. The story made national news, including this report from Denver's KWGN-TV.

The 1988 incident was one of several UFO sightings in Cheyenne. August 16, 1971, a guard at F.E. Warren Air Force Base in Cheyenne claimed he was abducted by aliens.

According to his account, John Renz was headed back to the barracks around 6:45 p.m. when he heard several strange noises and was approached by a mysterious being. His next memory was seven hours later when he was picked up by MPs.

Under hypnosis, Renz remembered being abducted and transported by aircraft to a facility where he was probed by aliens. He described the tan-skinned creatures between four and five feet tall with large eyes that resembled insects and three fingers on each hand.

 Renz also recalled seeing several bizarre symbols inside the saucer-shaped aircraft, which he estimated had 200 alien life forms on board. Before returning to the base where he was abducted, Renz claims he witnessed the aliens kill several smaller creatures with triangular heads.