This place is amazing, especially if your little girl likes the American Girl Collection. It is more than just a place to buy and look at beautiful dolls, its an education in manners, morals, and history. The museum boasts a store, theatre w/ live performances, and lots to see and do. A wonderful place for several girls to take a trip together. The only downside is that it can be pricey and should your little one desire a doll at the end of the trip, they are not the cheapest around, but seeing as this is located in NYC, you've probably brought some extra money anyway :)

The Franklin Institute has something exciting for everyone in the family, whether they are 3 years old or 90 years old. Everytime I visit, there is a new exciting exhibit to supplement the old favorites that have been there for 25+ years (like the huge human heart that you can acutally walk through!). I enjoyed this place as a child and look forward to enjoying it as a mother. It is also a great place to take the kids when the weather is bad as there is plenty to see and plenty of opportunities for them to expend their energy. There's also places to grab lunch in the museum, so you don't have to worry about finding a place for a bite to eat.

I am a Philadelphia native and growing up, my favorite thing to do in historical Philadelphia was visiting the Betsy Ross House. It is stone and partially below ground, so its a great stop on a hot summer day. The house truly gives kids and adults a taste of what it was like to live in a Philadelphia home at the time of the Revolution, as it is set up with period furniture, clothing, household items, and mannequins. It's also a realtively short tour, so it can hold the attention of younger children. Enjoy! ;)