Views of the greater Philadelphia area taken circa 1920s-1930s by Aero Service Corporation, an aerial photography firm established in Philadelphia in 1919.

[Construction of the Ridge-8th Street Subway.]
Aerial views of the Ridge-8th Street Subway (later known as the Broad-Ridge Spur) under construction. The approach to the Benjamin Franklin Bridge at 5th and Race Streets and the adjacent Franklin Square are visible, as is the area bounded roughly by Callowhill to the north, Market Street to the south, Front Street to the East and 10th Street to the west. The Ridge-8th Street Subway opened in 1932., Title supplied by cataloger., Date from manuscript note on negative sleeve: Eighth st. Subway, Frank. Square; Phila. Pa.; June 13, 1931., Negative numbers: 14407n.