Working on Catalina flying boat at the Corpus Christi Naval Air Base. August 1942. View full size. 35mm Kodachrome transparency by Howard Hollem.

Mating operation on a C-87 transport plane just before it comes to the pre- assembly line at the Consolidated Aircraft Corporation plant, Fort Worth, Texas. October 1942. View full size. Kodachrome transparency by Howard Hollem.

Fitting the tail of a C-87 transport plane to the wing center section in the fuselage mating fixture at the Consolidated Aircraft plant, Fort Worth, Texas. October 1942. View full size. 4x5 Kodachrome transparency by Howard Hollem.

Wing center section of a Liberator bomber at the Consolidated Aircraft plant. October 1942. View full size. Kodachrome transparency by Howard Hollem.

Medical classroom, American University of Beirut, Lebanon. Circa 1930s. View full size. (Warning - Not for the squeamish: See what's inside.)

Anatomy Class circa 1905. Location unknown. View full size. George Grantham Bain Collection.

New York, December 1924. "Greenwich Village Follies Cooking Class." George Grantham Bain Collection. View full size.

Cooking Class for Men at the Pratt Institute with Miss Hanks and Miss Kierstead, circa 1917. View full size. George Grantham Bain Collection.

Electricity Class at St. George's Evening Trade School, New York, circa 1910. View full size. George Grantham Bain Collection.

P-51 Mustangs of the 332nd Fighter Group (Tuskegee Airmen). Ramitelli, Italy, March 1945. Photo by Toni Frissell. View full size.

Old Ford's Theatre in Washington, D.C., where Abraham Lincoln was shot in 1865. View full size. Wet collodion glass plate. Photograph by Mathew Brady.

Federal soldiers killed July 1, 1863, near the McPherson woods. Gettysburg, Pennsylvania. View full size. Wet collodion glass plate, half of stereograph pair. Photograph by Timothy H. O'Sullivan.

View of ruined buildings through porch of the Circular Church at 150 Meeting Street, Charleston, South Carolina. April 1865. View full size. Wet collodion glass plate, half of stereograph pair. Photographer unknown. While much of the damage shown here is from shelling by the Federal Navy, the Circular Church itself was heavily damaged by fire in 1861. Alternate view.

Tuskegee airmen exiting the parachute room at Ramitelli, Italy. March 1945. From left: Richard S. "Rip" Harder, Brooklyn, Class 44-B; unidentified airman; Thurston L. Gaines Jr., Freeport, N.Y., Class 44-G; Newman C. Golden, Cincinnati, Class 44-G; Wendell M. Lucas, Fairmont Heights, Maryland, Class 44-E. Photo by Toni Frissell. View full size.

The Park Row Building at 15 Park Row circa 1912. View full size. For nine years this 1899 tower, at 391 feet, was the tallest in New York. Read more here. Irving Underhill photo.