This image was acquired from
flickr. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
sanitary ship canal excavation illinois chicago drainage blackandwhite monochrome outdoor black and white Cliff of Niagran limestone possibly part of Sanitary and Ship Chicago Drainage canal excavation series. . Original size and material inch glass negative Digital Identifier CSGEO Part of the Illinois Urban Landscapes Project