Cross the Rickenbacker Causeway from Downtown Miami, and soon you’re in a different world—a slower, quieter world. The resort town with palm-studded beaches shares a delicate barrier island with two public parks: Crandon Park to the north, and Bill Baggs Cape Florida State Park to the south. The beachfront Ritz-Carlton Key Biscayne and its swanky restaurants provide the glamour; the property’s Cliff Drysdale Tennis Center delivers the sweat. It’s one of the best tennis facilities in the country, with 11 courts.