AARP MEMBER DISCOUNTS SEE MORE

Most of the 19 Smithsonian museums are open between 10 and 5:30 more than 360 days a year, and all are free, though there may be charges for some special exhibits. During the spring and summer, many of the museums offer extended hours and close at 7:30. To get oriented, start with a visit to the Smithsonian building—aka the "Castle," for its towers-and-turrets architecture—which has information on all the museums.