Part of a vast estate off a quiet Georgetown street, the 10-acre garden of the Dumbarton Oaks Research Library and Collection is a celebration of landscape. Italian, French, and English garden traditions are all on display, from sharply trimmed boxwood topiary to rambling hillside flower patches to beds ablaze with lilies, roses, fuchsia, and oleander; in springtime, the cherry trees lining the brick paths and stairways are fluffy with blossoms. The gardens, and the villa they surround, were bequeathed to Harvard University in 1940; while residential areas are reserved for visiting scholars, the fragrant orangery, to the left as you approach the entrance, is open to all.
Tip: You won't see much ivy growing here, but admission is semper gratis for Harvard grads.
Admission: $8 mid-March to October; free November to mid-March. Closed Monday.