CENTRAL PARK
In between the Upper East Side and the Upper West Side, there lies the infamous Central Park, probably one of the most well-kown parks in the world.  It lies in a rectangle formed by 110th St. to the north, 59th St. to the south, Fifth Ave. to the east and Eight Ave. to the west.  It's a fun place, with activities for all ages.  Again, here are only a few pictures to show its beauty.
Here is a beautiful Maine Monument at the entrance on the South Side.
Here we a glimpse of the Mall walkway in Central Park where you can find some shade and a lot of benches. 
The Row Bridge over a lake in the middle of the Park.
Wouldn't you want to sit in the Great Lawn in the summertime and soak in the sunshine?