This graph at the FlowingData website caught my attention; it chronicles the growth of WalMart in the 45 years from 1962 to 2007, in a time-lapse movie format.
Walmarts are effectively wherever there is population; hence, the entire Eastern U.S. and the West Coast are lit up, but not the Rocky Mountain states. Of particular note is that the Adironacks in New York are apparant in their lack of Walmarts, yet the Blue Ridge Mountains and the Ozarks are not. In fact, practically none of the Appalachains are obvious.
Why is that?