Twenty hours. More than 30 miles of coastline. Dozens of moments captured. The photographer Todd Heisler walked the perimeter of Manhattan over the course of one day in August. While the route offers a different perspective on landmarks and topography, it’s the people that make the experience so rich. Class, ethnic mix and even age change gradually, depending on where you are. That can be witnessed in the picnics and parties, the sports that people play or even the simplest of routines.