The International Exhibition of Modern Art, organized by the Association of American Painters and Sculptors, took place in New York City's 69th Regiment Armory from February 17 to March 15, 1913. It displayed about 1,250 paintings, sculptures, and decorative works by over 300 avant-garde European and American artists, including Impressionists, Fauvists, and Cubists. Known as the Armory Show, this exhibition is credited with introducing "modern art" to the United States.
"News reports and reviews were filled with accusations of quackery, insanity, immorality, and anarchy, as well as parodies, caricatures, doggerels and mock exhibitions. About the modern works, President Theodore Roosevelt declared, 'That's not art!' The civil authorities did not, however, close down, or otherwise interfere with, the show.
"Among the scandalously radical works of art, pride of place goes to Marcel Duchamp's Cubist/Futurist style Nude Descending a Staircase, painted the year before, in which he expressed motion with successive superimposed images, as in motion pictures. An art critic for the New York Times wrote that the work resembled 'an explosion in a shingle factory,' and cartoonists satirized the piece" (Wikipedia article on Armory Show, accessed 03-13-2009).
In August 2020 a virtual recreation of the Armory Show prepared by the American Studies Program at the University of Virginia was available at this link. A collection of invaluable primary sources about the show was digitized and available from the Archives of American Art at this link.