"KKK parade on Pennsylvania Avenue, August 8, 1925." From the Washington Post's report: "Phantom-like hosts of the Ku Klux Klan spread their white robe over the nation's most historic thoroughfare yesterday in one of the greatest demonstrations this city has ever known. . . . Police estimated that there were 30,000-35,000 in the weird procession -- men, women and children of the Klan." National Photo Company Collection glass negative. View full size.

July 28, 1925. Washington, D.C. "Undelivered mail of World War soldiers (crucifix in bottle)." National Photo Company glass negative. View full size.

"Woman in automobile circa 1915." From of a series of pictures showing National Photo owner Herbert E. French and friends on motor excursions in the D.C. area. National Photo Company Collection glass negative. View full size.

July 18, 1925. Laurel, Maryland. "R.J. O'Connor, inter-city championship bicycle races, Laurel Speedway." National Photo Co. glass negative. View full size.

Washington, D.C., or vicinity, 1906. "Boys school baseball '06." Harris & Ewing Collection glass negative, Library of Congress. View full size.

February 5, 1865. "Abraham Lincoln, seated, holding spectacles and a pencil." Glass transparency; photograph by Alexander Gardner. View full size.

April 3, 1917. Oklahoma City. "Workshop of Sanitary Ice Cream Cone Co., 116 S. Dewey Street. Boys packing cones are John Myers, 14 years old, and a boy 12 years old who is working steady now. Boss said: 'He said he wasn't going to school so I took him.' " Photograph and caption by Lewis Wickes Hine. View full size.