UFO found in Colorado identified as Japanese balloon

Summary

In April 1949, a farmer in Delta, Colorado, reported finding pieces of a metallic aluminum ring-shaped object with 72 peripheral holes for explosive inserts. This discovery, made in 1946 but reported years later, was investigated by the U.S. Air Force as part of Project Grudge. Investigators concluded it was a ballast ring from a Japanese incendiary balloon used during World War II. Although initially speculated as a "flying disc," the analysis confirmed its earthly origin. The pieces were sent to Washington for analysis and the case was closed without further investigation.