REI Flagship StoreSprawling over 80,000 square feet, this timbered cathedral is a monument to all things outdoors. The Seattle landmark's spire, a 65-foot rock pinnacle, is the world's third-largest indoor rock-climbing wall. Take a class or just reserve a 15- or 30-minute time slot for a single climb ($15 for members, $25 for nonmembers). No experience is required; REI supplies gear from its Outdoor School. The store also has a mountain bike test track outside, as well as a small café and a tree house play area for kids.