While the bizarrely named Piggly Wiggly is not America's biggest supermarket today, it's widely credited as being the first self-serve grocery store in the United States. Before Piggly Wiggly opened its doors in 1916 in Memphis, Tennessee, store clerks would take a list from customers and gather the required products themselves. Piggly Wiggly, with its carefully stacked shelves, turnstiles and wooden shopping baskets, was something of a revolution.