Beautiful on the outside, the 1855 Medieval-style building with its eight crenellated towers and rich red sandstone facade lives up to its nickname. Its Great Hall interior is pretty unattractive, but that doesn’t matter, because you’re here for information, possibly restrooms, and perhaps a bite to eat. Watch the 10-minute orientation video, take a look at the National Mall models in the middle of the room, and, most important, stop by the information desk to ask the multilingual staff of volunteers to help you plan your Smithsonian itinerary.

There’s not much else in this big building that’s open to the public. The remains of Smithsonian benefactor James Smithson are buried in that big crypt in the Mall-side entrance area, which includes a small exhibit about the man. The pretty south-side entrance has been repainted to appear as it did in the early 1900s, when children’s exhibits were displayed here. The Commons area and Schermer Hall, on the west side of the building, sometimes are used as small exhibit areas highlighting works from surrounding Smithsonian museums. On the east side of the building is the Castle Café, which opens at 8:30am, earlier than any other building on the Mall. Coffee, pastries, sandwiches, and even beer and wine are sold. Situate yourself at a table inside, where there’s free Wi-Fi, or outdoors in the lovely Enid A. Haupt Garden, and plot your day.