Famed for its regal Old Master painting collection, the Dulwich (pronounced "Dull-ich") Picture Gallery was Britain's first purpose-built art museum when it opened in 1811. The permanent collection includes landmark works by Rembrandt, Van Dyck, Rubens, Poussin, and Gainsborough, and it also hosts three major international exhibitions each year. The gallery has a lovely café serving meals and drinks, and there's a schedule of family activities (see website for details).
Development in Dulwich Village is tightly controlled. Consequently, it feels a bit like a time capsule, with old-fashioned street signs and handsome 18th-century houses lining its main street. Take a short wander and you'll find a handful of cute clothing and crafts stores and the well-manicured Dulwich Park, which has lakeside walks and a fine display of rhododendrons in late May.