These gas masks were reconditioned at the Edgewood Arsenal for civilian defense use during World War II. Later, in the 1950s and '60s, the arsenal near the Chesapeake Bay was used for secret chemical weapons testing run by the U.S. Army. Jack Delano/Library of Congress hide caption

Jazz great Charles Mingus performs at the Monterey Jazz Festival in September 1964. Ray Avery/CTS Images hide caption