Denver's REI flagship store, one of three such shops in the country, is yet another testament to the city's adventurous spirit. The store's 94,000 square feet are packed with all stripes of outdoors gear and some special extras: a climbing wall, a mountain-bike track, a whitewater chute, and a "cold room" for gauging the protection provided by coats and sleeping bags. There's also a Starbucks inside. Behind the store is the Platte River Greenway, a park path, and water area that's accessible to dogs, kids, and kayakers.