Fresh out of college, the Wal-Mart founder cut his teeth in a J.C. Penney management training program. Later, he ran a chain of five-and-dime stores in the South.

He left that discount retailer -- Ben Franklin -- over a fallout with company management. Walton wanted to expand to other small rural towns, but management wanted to stick to the old formula of locating stores in and around big cities.

So Walton founded Wal-Mart (WMT), and pioneered a concept of stocking several smaller stores from a centrally located distributor -- a model that remains key to the success of big box retailers.

Wal-Mart is now the country's largest retailer, and Walton's heirs are worth over $130 billion combined.