The Smithsonian National Portrait Gallery

After being closed for six years for renovation, the Smithsonian’s National Portrait Gallery in Washington reopened in July 2006, with 57,000 square feet of exhibition space. (That’s a lot of portraits!) One of the most innovative things is the putting of the Lunder Conservation Center on public display. Ceiling-to-floor windows let museum visitors watch what the museum’s conservators are doing.

• Info on Visiting the National Portrait Gallery from About's DC/Capital Region Guide.