This elegant palace holds the 16th- and 17th-century painting collection of the Galleria Nazionale d'Arte Antica; even if you're not interested in the paintings, stop in to climb the extraordinary 17th-century stone staircase, itself a drama of architectural shadows and sculptural voids. The adjacent Corsini gardens, now Rome's Giardino Botanico, offer a welcome break with native and exotic plants and a stunning view at the top. COST: EUR4.