People dancing on a dancefloor.
Source: Library of Congress Prints and Photographs Division. New York World-Telegram and the Sun Newspaper Photograph Collection. http://hdl.loc.gov/loc.pnp/cph.3c34893. http://en.wiktionary.org/wiki/File:Jitterbug_dancers_NYWTS.jpg
Author: New York World-Telegram and the Sun staff photographer: Fisher, Alan, photographer.