"Dome Oil Co., Takoma Park." In Maryland in 1921, a gritty diorama of the Petroleum Age. View full size. National Photo Company glass negative.

Nov. 1941. Etna, Pennsylvania. "Blast furnaces and ore at the Carnegie-Illinois Steel mills." View full size. 4x5 Kodachrome transparency by Alfred Palmer.

Boston, Massachusetts. January 25, 1917. "Boys linking bed-springs. 14 and 15 years old." Glass negative by Lewis Wickes Hine. View full size.

East Room of the White House circa 1920. View full size. National Photo Co.

Washington, D.C. "Union Station concourse. 1921 or 1922." I count at least six people in this time exposure. View full size. National Photo glass negative.

Washington, D.C., or vicinity circa 1926. "Southern R.R. Co. Crescent Locomotive 1396." View full size. National Photo Company Collection glass negative.

Washington, D.C., circa 1920s. "Union Station signals and tracks." National Photo Company Collection glass negative, Library of Congress. View full size.

"Service station, First Street and Maryland Avenue." Spectacularly detailed view of the Capital Gasoline Station in Washington, D.C., in 1922. View full size. National Photo Company Collection glass negative. View even larger.

Washington, D.C. "American Nature Association. Between 1910 and 1926." It's probably safe to say this is 1925. September 14, to be specific. A Monday (boo). View full size. National Photo Company Collection glass negative.

Electrical circuits and motors at Howard University in Washington, D.C., circa 1925. View full size. National Photo Company Collection glass negative.

"North Capitol Tire Shop, 1919 or 1920." Approaching the camera: A two-horsepower biofuel vehicle. National Photo Company. View full size.

"Ansell, Bishop & Turner window display. 1920." A Victrola dealer in Washington, D.C., puts Nipper in the game. View full size. National Photo Co. glass negative.

Funhouse at the Glen Echo amusement park in Maryland circa 1925. Note the many cryptic signs. View full size. National Photo Company glass negative.

"Glen Echo, 1928." Riding the Whip at Glen Echo amusement park in Maryland. View full size. National Photo Company Collection glass negative.

Bumper cars at the Glen Echo amusement park in Montgomery County, Maryland, circa 1928. National Photo Company Collection glass negative. View full size.