Mariana was the general manager of the Great Falls, Montana, "Electrics" baseball team when, at approximately 11:25 a.m. on August 15, 1950, he filmed just over ten seconds of what he claimed to be two unidentified flying objects. This film is thought to be the first known filmed UFO sighting. Mariana, along with his secretary Virginia Raunig, were inspecting the baseball field when they saw two disk-shaped silvery objects in the sky that appeared to be rotating. He got his 16-mm color movie camera from his car and the resulting short film was sent to the Air Force for analysis but eventually explained away as "possible aircraft." In 1955, Dr. Robert M. L. Baker of Douglas Aircraft conducted his own detailed analysis of the film. His conclusion was that the images had to be moving faster than jets could fly in 1950. Later studies of the film concluded as well that the aircraft explanation is not possible. Mariana himself, as well as one second of the color film, appeared in the otherwise black-and-white 1956 documentary "Unidentified Flying Objects: The True Story of Flying Saucers.".