NPR: How I built this

In the early 1990s, Susan Griffin-Black was working for Esprit in San Francisco. On a business trip to London, she walked into a Covent Garden apothecary shop, picked up a bottle of lavender oil and took a whiff. The aroma — "like being in a beautiful garden" — literally changed her life. That was the inspiration to develop her own line of essential oil products. For 15 years, she and her husband and co-founder Brad Black barely scraped by, but the business eventually thrived. And though their marriage ultimately ended, their partnership continues. PLUS for our postscript "How You Built That," Lia Heifetz of Barnacle Foods describes how she and her partners turned Alaskan bull kelp into pickles and salsa.

In 1989, college senior Wendy Kopp was trying to figure out how to improve public education in the US. For her senior thesis, she proposed creating a national teaching corps that would recruit recent college grads to teach in needy schools. One year later, she launched the nonprofit, Teach for America. Today, TFA has close to 60,000 alumni and continues to place thousands of teachers across the country. PLUS in our postscript "How You Built That," we check back with 19-year-old CEO Abby Kircher who turned a peanut butter obsession into Abby's Better Nut Butter.

Dave Dahl's entrepreneurial journey began in prison. In 1987, he was addicted to drugs and incarcerated for home burglary. For 15 years he bounced from one sentence to the next. But in the mid-2000s, Dave returned to his family bakery where he was inspired to make bread – organic, nutty, and slightly sweet. He sold the loaves at farmers markets and shared his story of recovery on the package – a branding decision that attracted fans and media attention. In 2015, the Dahl family sold the business for $275 million dollars. Today, Dave's Killer Bread sells over a dozen types of bread in grocery stores nationwide. PLUS in our postscript "How You Built That," armpit entrepreneurs Jason and Erica Feucht tell us how they turned whiskey and vodka into the natural deodorant Pit Liquor.

In 2004, two former Paypal engineers, Jeremy Stoppelman and Russ Simmons, were spit-balling new internet ideas. Out of their brainstorm came a site where you would email your friends asking for local business recommendations. The launch was a flop, but they discovered that people seemed to enjoy writing reviews not just for friends, but for the general public. Fifteen years later, Yelp is a publicly traded company with more than 4,000 employees and over 140 million monthly visitors. PLUS in our postscript "How You Built That," Liz Bales explains how putting cat food inside plastic mice became her full-time business and why it could revolutionize the way humans feed their cats.

Twenty-five years ago, after Mei Xu emigrated from China to the U.S., she loved going to Bloomingdale's to gaze at their housewares. She eventually started making candles in her basement with Campbell's Soup cans, an experiment that led to the multi-million dollar company Chesapeake Bay Candle. PLUS in our postscript "How You Built That," we check back with Dan Kurzrock and Jordan Schwartz, who turned up-cycled beer grain into a snack bar called ReGrained.