When I was a kid in Brooklyn, you were taking your life in your hands venturing deep into Prospect Park, but now... It's Beautiful!!!
They have great hike trails throughout Prostect Park with bird watching, wildlife, a lake, waterfalls (small ones) and gravesites with stones you would have to take rubbings of to determine the name and date on them.
They have guided tours and maps of the park for hiking also.
For more information click here: