Project Blue Book Case #4127. On June 6, 1956, witnesses in Banning, California — a community in the San Gorgonio Pass between the San Bernardino and San Jacinto mountains — observed a bright object in the sky. The pass served as a natural corridor connecting the Los Angeles Basin with the Coachella Valley and the Colorado Desert.
Banning's position in the pass placed it near March AFB (a SAC installation approximately 20 miles to the west) and within the broader Southern California aerospace corridor. The pass itself was a natural wind corridor and a landmark navigation feature for both civilian and military aviation.
No conventional explanation was found. The case was classified "Unknown."