Uruguay, May 1958May 1958

On May 25, 1958, an instructor pilot and aviator named Carlos Alejo Rodrigues was flying a Piper aircraft from San Carlos to Montevideo, Uruguay, when he spotted an unusual object in the sky ahead of him. The object was bright and shiny, shaped roughly like a spinning top with a flat upper section and a pointed bottom. It hung in the air at approximately 700 meters altitude, roughly level with his plane.

Rodrigues watched as the object suddenly stopped and hovered motionless for a moment. Then it began to rock or oscillate side to side twice, before accelerating sharply toward the north with what he described as fantastic speed. The entire sighting lasted about ten minutes. As the object departed, it left behind a small trail that resembled water vapor. Rodrigues also noted that he felt a noticeable increase in temperature during the encounter, though he could not account for the source.

The Uruguayan Centro de Investigaciones de Objetos Voladores Inidentificados, a civilian UFO research group affiliated with the country's air force intelligence service, conducted the investigation. The group noted that Rodrigues had a reliable personality and that his account contained no contradictions. They highlighted five key features of the sighting: the object's shape, its sudden movement, its rapid acceleration, the temperature increase, and the characteristic oscillation, all of which matched the typical descriptions of flying saucer reports. The group concluded the case was credible and marked it as one of the first sightings in a new wave of UFO reports in Uruguay during the second quarter of 1958.

The Air Force evaluation listed the case conclusion as "unknown" due to insufficient data. The full case file, consisting of 12 pages held by the National Archives, is reproduced below.