The American Museum of Natural History is filled with everything you could imagine: artifacts, gems, animals, and dinosaurs. In fact, if you want to read a lot of the information in every section, I would recommend TWO days so that you can take your time.
*Tip: I recommend getting there right when it opens! You have to remember this is one of the most famous museums in the world, so it's always crowded!
**If you can't get there right away, buy your tickets ahead of time online or go in the self service ticket line once you're there (the line may look big, but it's the quickest)!
***Pack your own lunch and bring it to the cafeteria to eat! I have never seen a more unorganized and overpriced food court (the prices were worse than Disney)! That was my only complaint about the whole museum.