December 22, 1925. Washington, D.C. "Dick Nash, Pony Ballet." (My first thought on seeing this: How did my vacation photos end up on the Internet?) 4x5 glass negative, National Photo Company Collection. View full size.

June 30, 1925. "Miss Dorothy Brautigam of the National American Ballet." National Photo Company Collection glass negative. View full size.

New York, 1917. "Washday on landship Recruit." Sailors doing their laundry on the Navy's pretend battleship moored at Union Square, used for recruiting during World War I. In back is the Automatic Vaudeville penny arcade, two of whose backers -- Marcus Loew and Adolph Zukor -- went on to found Metro-Goldwyn- Mayer and Paramount Pictures after a few years in the nickelodeon business. 5x7 glass negative, George Grantham Bain Collection. View full size.

Interior of the Holiday Shop record and camera store at the Roeland Park Shopping Center in Roeland Park, Kansas. View full size. [A fascinating member-submitted photo. Just the thing for a Saturday night. Like a number of the commenters below, I would place the date here around 1950-51. - Dave]

Houston, October 1913. Marion Davis, Messenger #21 for Bellevue Messenger Service. Fourteen years old. "Been messenger, off and on, for two years. Not supposed to go to the Reservation [Red Light] under sixteen years, but I do just the same. The boss don't care and the cops don't stop me." View full size. Photograph and caption by the indefatigable Lewis Wickes Hine.

August 18, 1924. Washington, D.C. "Miss Beatrice Beck, daughter of Solicitor General James M. Beck." View full size. National Photo Company Collection.

1862. The Peninsula, Virginia. "Lt. George A. Custer with dog." Photographs from the main Eastern theater of war, the Peninsular Campaign, May-August 1862. Wet plate glass negative, photographer unknown. View full size.

Washington, D.C., 1925. "Miss Mary B. Hoover." No further clues as to the significance of this person. [This just in: Miss Hoover is "an authority on the proper fitting of Children's shoes."] View full size. National Photo Company.

"Harlan Randall, 1925." At various times Harlan was a baritone with the Washington Opera and head of the music department at the University of Maryland. View full size. National Photo Company Collection glass negative.

1925. The Triangle Service Station in Arlington, Virginia, at Mount Vernon Avenue and Military Road. View full size. National Photo Company Collection.

July 9, 1926. "Golf and bathing suits." For the first day of summer, we revisit the lovely ladies seen here a few days ago strumming ukuleles. Now they're on the links with an early air-conditioned golf cart. View full size. National Photo Co.

Fort Knox, June 1942. "Light tank going through water obstacle." View full size. 4x5 Kodachrome transparency by Alfred Palmer, Office of War Information.

1924. "Children of Mrs. Milan Getling" (actually Getting). National Photo Company Collection glass negative. View full size.

June 1942. "Why greases must be saved. Introducing two good soldiers of the home front: the housewife who saves her waste household fats and greases, and the butcher to whom she gives this salvaged fat after she has collected at least one pound, strained it through a metal sieve and poured it into a large, wide-mouthed can. Butchers displaying the poster shown here will pay househoulders for the fat, and sell it to rendering plants thereby turning this valuable material into industrial channels where it will be processed into ammunition for America's fighting men." Medium format negative by Ann Rosener for the OWI. View full size.

6 p.m., May 18, 1909. Somersworth, New Hampshire. "Group of boys working in Great Falls Manufacturing Co. Smallest boy is Alfred Ouellet, 212 Main Street. Fat boy is Willie Laudry, 35 South St. Boy on right hand end is Napoleon St. Lawrence, 23 Union Street." View full size. Photo and caption by Lewis Wickes Hine.