Project Blue Book Case #4577. On December 31, 1956, an unidentified object was observed over Guam — the western Pacific island that hosted Andersen Air Force Base, a major SAC bomber installation. Andersen's B-36 and later B-52 bombers could reach targets across Asia, and the base was a critical component of the Pacific nuclear deterrent.
New Year's Eve timing and the remote Pacific location made this case unusual. Guam's isolation — over 3,000 miles from Japan and 6,000 from Hawaii — meant extremely limited conventional air traffic. The case was classified "Unknown."