DC was built on a marsh, a beautiful, brackish, low-lying ripple of saw grass and steel-blue water, wind-coaxed and tide touched by the inflow of the Potomac from Chesapeake Bay. You’d never know all that now, of course, unless you come to the USA's only national park devoted to water plants. See the natural wetlands the District sprang from; look out for beaver dams, clouds of birds and the more traditional manicured grounds, quilted in water lilies and lotus.
The aquatic gardens were begun as the hobby of a Civil War veteran and operated for 56 years as a commercial water garden, until the federal government purchased them in 1938. The park is about a mile walk from the Metro. Depart the station from the lower Polk St exit and take the pedestrian overpass across Kenilworth Ave. Go left on Douglas St, then go right on Anacostia Ave and enter any gate on your left.