The site of Washington's oldest amusement park (1911-68) is preserved here, as is a stone tower from the village of Glen Echo, founded in 1891 by Edwin and Edward Baltzley, brothers who made their fortune from the invention of the eggbeater. The brothers were enthusiastic supporters of the Chautauqua movement, a group begun in 1874 in New York as a way to promote liberal education among the...