New York City tops the list, thanks to its size, population density and age. It was also No. 1 in the experts’ original survey. The New York metropolitan area's population is the nation's largest, estimated at 18.8 million people over 6,720 square miles. The bright side: For a peek at more desirable animals, there's the Central Park Zoo, which also has the Tisch Children's Zoo where the little ones can get up close and personal with ducks, goats, sheep, alpacas and other barnyard creatures. Don't forget the Queens Zoo, Prospect Park Zoo and Bronx Zoo.