If your trip to Upper East Side is all locked in but your itinerary is looking a little empty, let us give you a helping hand.Greatest things to explore around the neighborhood? Metropolitan Museum of Art and Solomon R. Guggenheim Museum are right up there. Head over and find out what they're all about.Leave that rental car back at the hotel and exercise those legs. Not far from the center of this neighborhood, Central Park is worth a look. More adventure is waiting for you at American Museum of Natural History and Central Park Zoo, which are also nearby.