A decade ago, full-time mom Alli Webb noticed a gap in the beauty market: there was nowhere that just focused on blow-drying hair. Now with 70 locations, Drybar is testament to Webb's motto: Focus on one thing and be the best at it.

Zumba began as a mistake: aerobics teacher Beto Perez brought the wrong music to class, then improvised a dance routine to go with it. For his students, it was more fun than work — and it eventually grew into one of the biggest fitness brands in the world.

In 2008, it was nearly impossible to buy a fashionable, affordable pair of glasses online. That simple frustration inspired the idea behind Warby Parker – and disrupted the eyewear industry.

Melissa and Doug Bernstein's first success was a wooden 'fuzzy puzzle' of farm animals. Today, Melissa & Doug makes over 2,000 kinds of toys and serves as an antidote to the rise of digital toys.

Mark Cuban made millions off of tech startups, then billions off of stocks — and later went on to buy and revive the Dallas Mavericks. He has come to define the persona of the serial entrepreneur.

In 1968, competitors sued to keep Herb Kelleher's new airline grounded. After a 3-year court fight, the first plane took off from Dallas. Today Southwest Airlines operates nearly 4,000 flights a day.

As a kid, José Andrés tended fires for his father's backyard paella cookouts. Later, he trained with the best Spanish chefs, and began building a restaurant empire that would transform the way many Americans dine out.

L.A. Reid began his music career as a drummer. Then he co-founded LaFace Records, discovering dozens of future pop superstars. Reid is now one of the most influential executives in the music industry.

Jane Wurwand moved to Los Angeles with a suitcase and a beauty school diploma. She started what would become Dermalogica, an international beauty empire that set the standard for skin care.

Suroosh Alvi was a recovering addict when he started a scrappy underground magazine in Montreal. It grew into VICE Media — a multi-billion dollar company that has shaken up the world of journalism.