For Uber fans, the “White Unicorn” has become the stuff of San Francisco legends. The elusive white car—the only one in Uber’s all-black fleet—accomplishes Herculean feats, having even whisked one woman off her feet to a surprise engagement party. When not busy playing matchmaker, though, the Unicorn and its faithful driver, Sofian, can be found deftly battling rush-hour traffic on San Francisco’s winding streets, getting Uber users to their destinations.

Fasten your seat belts: Uber is an on-demand car service that’s shaking up the transportation systems in 20 cities (and growing) around the world. Customers use the Uber app, website, or text message service to connect with the nearest available driver. Customers can choose which kind of vehicle they want—from basic taxis to snazzy limousines to hybrid vehicles—and have their ride show up within minutes of their request.