The playground has been five years in the making, a result of tons of research in progressive learning theory and child-development research, as well as $7.4 million in financing. In smaller, portable versions, it has been tested and tweaked after trial tours all over the city.

Instead of monkey bars and jungle gyms, there are fountains with canals of cascading water that can be dammed in infinite ways, or transformed into a network of rivers. There is an engaging set of lifts and pulleys. Play is proctored and interaction fostered by a staff of city workers trained as “play associates.”