UFO seen in Pueblo, Colorado, with white smoke-like shape

Summary

An object was sighted in Pueblo, Colorado, for 20 minutes on the night of December 1, 1955. It was described as a white cloud resembling a cigarette smoke, glowing at the top. Although an aircraft was considered, its speed was too slow for a jet and there was no normal air traffic in the area. The object disappeared behind the mountains without a trace. The report concluded it could be a contrail from a high-flying aircraft. This case is part of a series of sightings in 1955 analyzed during the Cold War context.