The Brooklyn Museum is a huge art museum, displaying works spanning from Ancient Egypt to modern art. It's a pretty spectacular place!
Here's an interesting one: a rooftop dropped into the fifth floor rotunda (called The Eastern Oracle: We Will Tear the Roof Off the Mother) that you can climb in and around and on! We opted for on, of course. My dad and Scott climbed on it first. This is when my dad was getting trouble for climbing on the roof holding something in his hand. Safety hazard!
Brooklyn Botanical Gardens is right next door to the Museum, so we popped over there for a stroll as well. First of all: it is gigantic. We walked and walked and walked and never ran out of flowers. Second of all: simply beautiful. I'll let these flowers speak for themselves (and there are also trees and herbs and ponds and shrubs and tons more too!).
When you come visit the city, make sure you take a day for Brooklyn - it has much, much more to offer than even these treasures!