Historic American Buildings Survey/Historic American Engineering Record/Historic American Landscapes Survey, 1933-PresentAdministered since 1933 through cooperative agreements with the National Park Service, the Library of Congress, and the private sector, ongoing programs of the National Park Service have recorded America's built environment in multiformat surveys comprising more than 556,900 measured drawings, large-format photographs, and written histories for more than 38,600 historic structures and sites dating from Pre-Columbian times to the twentieth century. This digital collection includes images of measured drawings, black-and-white photographs, color transparencies, photo captions, written history pages, and supplemental materials.