Like many constructions in Las Vegas, the Miracle Mile Shops at Planet Hollywood is not an original concept, but rather takes its name from L.A.'s Miracle Mile, the stretch of Wilshire Boulevard bought and developed in the 1920s by A.W. Ross, who had the vision to transform it from a narrow dirt track into a busy retail destination, aided by the rise of the personal automobile. Ross originally named it Wilshire Boulevard Center, but later renamed it the Miracle Mile after a friend of his joked about how excited Ross was about his project, or so the story goes. Today it's known best for the La Brea Tar Pits and some historic Art Deco architecture.
As for the Las Vegas version, this also started out under a different moniker, debuting as Desert Passage with the newly reincarnated Aladdin, back in the summer of 2000. That whole enterprise was pretty much doomed from the start, blighted not least by animosity between the hotel-casino and the separately owned adjacent mall, neither of which promoted the other. The entries to both entities were obscure and uninviting, and the whole debut of the resort-casino was marred by construction delays, massive overspends, and a fiasco of a grand opening that saw fireworks canceled by the Fire Department, check-in and valet staff sporting hard hats (which were not offered to guests, although frankly, who would want one?), festivities drowned out by the vocal protests of the Culinary Workers Union, and a casino where the very first bank of machines to greet guests as they entered were all out of commission, marked with hastily-prepared "Out of Order" signs.
By 2003 both facets of the new development were in trouble, and the casino sold to a partnership between Starwood Resorts and Planet Hollywood. The whole Arabian theme, which had never made much sense, was axed and the shopping mall, which was also sold, was re-branded as The Miracle Mile Shops, presumably in an effort to evoke an upscale urban vibe, with some new retailers in place and no more fake thunderstorms or belly dancing.
Your question is actually a timely one since right now, the indoor mall comprises 170 stores and restaurants in a 475,000-square-foot space and is actually 1.2 miles long ("The Miracle Mile and a Bit" doesn't sound quite as compelling, somehow). Some big expansion plans were announced recently, however. The new project calls for a 60,000-square-foot area on the center’s south end, at Harmon Avenue, to be converted into yet another indoor/outdoor dining and entertainment complex that's currently on the architect's drawing board. Construction is due to commence at some point next year, but in the meantime new stores will continue to open throughout the existing Miracle Mile. Visit the official website for a complete list of current retail outlets, dining destinations, and entertainment venues.