Make this your first stop. Built in 1855, this Norman-style red-sandstone building, popularly known as the "Castle," is the oldest building on the Mall, yet it holds the impressively high-tech and comprehensive Smithsonian Information Center.

The main information area here is the Great Hall, where a 24-minute video overview of the institution runs throughout the day in two theaters. There are two large schematic models of the Mall (as well as a 3rd in Braille), and two large electronic maps of Washington allow visitors to locate nearly 100 popular attractions and Metro and Tourmobile stops. Interactive videos, some at children's heights, offer extensive information about the Smithsonian and other capital attractions and transportation (the menus seem infinite).

The entire facility is accessible to persons with disabilities and information is available in a number of foreign languages. Daily Smithsonian events appear on monitors; in addition, the information desk's volunteer staff can answer questions and help you plan a Smithsonian sightseeing itinerary. Most of the museums are within easy walking distance of the facility.

While you're here, notice the charming vestibule, which has been restored to its turn-of-the-20th-century appearance. It was originally designed to display exhibits at a child's eye level. The gold-trimmed ceiling is decorated to represent a grape arbor with brightly plumed birds and blue sky peeking through the trellis.