Watch American Experience Season 14 Online

"City of Tomorrow (1929-45)" focuses on Mayor Fiorello LaGuardia, who used his close ties to FDR to make the city "a gigantic laboratory of civic reconstruction"; and master builder Robert Moses, who "adapted a 19th century city to 20th century circumstances," says historian Kenneth Jackson. The biggest one: the car. Says narrator David Ogden Stiers: "It challenged all previous assumptions about urban life."