Sunset Silhouette of a Flying Fortress
This picture was found in a collection on the Library of Congress's website, an idea I took from Doug over at Macalicious. It is a B-17 'Flying Fortress' at Langley, Virginia, in July 1942. The photograph is credited to Alfred T. Palmer, and for more information, go here. I personally think it's one of the greatest photographs of an aircraft ever taken.