Demolished Buildings--Pennsylvania--Philadelphia--20th century American Revolution Bicentennial, 1776-1976--Pennsylvania--Philadelphia 1 Architectural elements--Pennsylvania--Philadelphia 1 Architecture--Philadelphia--20th Century 1 Built environment--Pennsylvania--Philadelphia--20th century 1 Constitutional Bicentennial 1 Parades and Processions--20th century 1 more ... Photographs--Street scenes 1 Photography--Philadelphia street scenes--20th century 1 Urban Blight--Philadelphia--20th century 1 less ...