Picryl description: Public domain historical photo of Washington DC during the First World War, free to use, no copyright restrictions image.
Picryl description: Public domain image of a worker, labor, factory, plant, manufacture, industrial facility, 1930s, mid-20th-century industrial photo, free to use, no copyright restrictions.
Picryl description: Public domain image of a commercial or residential multi-story building, condominium, 20th century, free to use, no copyright restrictions.
Picryl description: Public domain image of a factory, plant, manufacture, assembly line, industrial facility, early 20th-century industrial architecture, free to use, no copyright restrictions.