Philadelphia the Manufacturing and Industrial Capital map, 1906
“Philadelphia Underground,” Jan. 29, 1961
“Sewer Crawlers,” January 29, 1961
1779 Revolutionary War-era map of Philadelphia and environs
Nine visiting nurses ready for work, ca. 1909
Plan for the Collection, Purification and Disposal of the Sewage of the City of Philadelphia, 1912
Jar of raw sewage before treatment, 2000
