The Reynolds Center is one of DC's finest museums. This Smithsonian venue combines the National Portrait Gallery and the American Art Museum into one whopping collection of American art that's unmatched anywhere in the world. Keep an eye out for famed works by Edward Hopper, Georgia O’Keeffe, Andy Warhol, Winslow Homer and loads more celebrated artists.
Be sure to hit the Luce Foundation Center on the 3rd and 4th floors: the open storage area stuffed with more than 3000 paintings, sculptures, miniatures and folk-art pieces makes for glorious browsing. The museum's glass-roofed inner courtyard on the 1st floor, dotted with trees and marble benches, is another lovely spot. Bring your own picnic or order sandwiches at the cafe.