This will help you plan walking trips in Manhattan, and ration your stamina as you go: there are about twenty street blocks to a mile (72nd Street to 92nd Street) and about six avenue blocks to a mile (from 11th Avenue to Fifth Avenue).
In Central Park, and especially in The Ramble, it is easy to become disoriented and even lost. The paths curl and twist and you can’t see any landmarks for the forest. What to do? Find a lamp post. Look carefully for its identifier tag; there is a small, rectangular plate affixed to nearly every lamp post. The first two digits represent what street you would be on if the streets ran clear through the park.
This photo shows a lamp post located between the Sheep Meadow and Strawberry Fields, correctly identifying its location as being near the line that connects 70th Street were it to run through the park to the east side.
One blizzardy night a few years ago I tracked a coyote through the park by following the direction from which it had come, to its den in The Ramble. These identifying plates helped me figure out exactly where that den was. To this day, only I (and the coyotes) know!