Old San Juan
Puerto Rican governors have resided in this structure (originally a fort) since 1543, though it wasn't named the governor's official residence until 1822. In fact, it's the Western Hemisphere's oldest executive mansion that's still in use. Tours of the building's first floor, including the chapel, dungeon, and the gardens, are given on a daily basis. For inside access, take the hour-long VIP tour, which goes onto the second floor through the ancient throne room, audience halls, and governor's office (yes, you might meet him). Special tours must be arranged in advance through a written request. Call for more details.