Unidentified object observed over Sisimiut, Greenland — second Arctic unknown (1953)

Project Blue Book Case #2606. On June 24, 1953, an unidentified object was observed over Sisimiut (formerly Holsteinsborg), Greenland — the second Blue Book unknown from this strategically vital Arctic territory (following the Prince Christian case of 1954). Greenland's position along the polar bomber route and the DEW Line made any unexplained aerial activity a matter of highest concern. June 24 was the sixth anniversary of Kenneth Arnold's sighting. The case was classified "Unknown."