The NFL is mighty today, but believe it or not, features a humble past.

The story of the National Football League is the foremost success story in the annals of American sports. Baseball may continually be called "the national pastime," in recent decades, pro football has turned into a national obsession. Pro football is undoubtedly, the hottest sport in America, its tens of millions of impassioned fans turning the NFL into a rapidly growing multibillion-dollar business.

This fall, more than 17 million people will attend an NFL game in person. Countless millions more—an estimated three out of each and every four American men, women, and children—will watch a minumum of one game on television. The league's championship game, the Super Bowl, will undoubtedly be celebrated next February as a digital national holiday, the best day of the season not only for sports, but in addition for the tv screen, advertising, and snack food industries.

Today, it's hard to trust that the National Football League, this behemoth of American sporting culture, was founded as a humble association of four teams you've never heard of—the Akron Pros, Canton Bulldogs, Cleveland Indians, and Dayton Triangles—meeting in a Canton, Ohio automobile showroom after the close of business one night in 1920.

None of the NFL's charter teams might even afford to pay for the nominal franchise fee of $100, worth about $1,000 today. For a long time, the NFL struggled merely to survive. Its franchises collapsed with disturbing frequency—at least 43 short-lived NFL teams went defunct in the league's first dozen years of existence—since the pro game struggled to get fans and establish its legitimacy in a sports world dominated by Major League Baseball, heavyweight boxing, and college football.