If you believe sprawl just magically happened, here's something that visually suggests otherwise. Thanks to researchers at the University of Richmond, Mapping Inequality offers unprecedented online access to the national collection of 'security maps' produced between 1935 and 1940, that doomed thousands of inner city neighborhoods to the negative effect of redlining.

Largest 10 U.S. Cities in 1940

1. New York - 7,457,995 (1940 Census)

2. Chicago - 3,396,808

3. Philadelphia - 1,931,334

4. Detroit - 1,623,452

5. Los Angeles - 1,504,277

6. Cleveland - 878,336

7. Baltimore - 859,100

8. St. Louis - 816,048

9. Boston - 770,816

10. Pittsburgh - 671,659