Project Blue Book Case #3427. On February 10, 1955, a bright object was observed over Bethesda, Maryland — the second Blue Book unknown from this Washington suburb (following Case #1128 from April 1952). Bethesda was home to the National Institutes of Health and the National Naval Medical Center, and the CIA's future headquarters at Langley was under construction nearby.
Bethesda's concentration of federal scientific and intelligence facilities made it one of the most security-conscious communities in the country. Its position within the Washington air defense zone meant comprehensive radar and air traffic monitoring. The repeat occurrence of unknowns over Bethesda reinforced the phenomenon's persistence in the capital region.
The case was classified "Unknown."