A self-taught photographer from Detroit, Harry Callahan became one of the most respected photographers of the 20th century and mentored a generation of students at Chicago’s Institute of Design. He once modestly described his subjects as “nature, buildings, and people,” and his photographs of architecture share a hallmark frontality and simplicity. In this image of an airplane hangar, Callahan masked off part of his 8 × 10–inch negative to emphasize the building’s horizontal form. The Art Institute purchased this photograph from the photographer a year after granting Callahan his first one-man museum exhibition.