Designed by Olmsted and Vaux of Central Park fame, Prospect Park opened in 1867. It’s the borough’s playground, where 10 million people a year come to explore the Ravine, Brooklyn’s only forest; skate year-round at the LeFrak Center at Lakeside; sample food from 100 local vendors at Smorgasburg; commune with nature at the Audubon Center; and picnic on the lush green of Long Meadow.