On nights when the Spanish Ballroom at Glen Echo Park fills to capacity, Park Ranger Stan Fowler escapes from the live music to the crawl space beneath the maple floor. There he listens to a different musical ensemble.

Above his head, the historic floor he restored gives as toes tap, heels grind and stomp, feet land from jumps and hops. A contra dance, a type of folk dance, flows in perfect lines of synchronized sound. Waltzes gently sweep past. Swing and Cajun steps are accented by sporadic thuds.