The Tattered Cover bookstore in Cherry Creek was a beloved gathering place, but the building that housed it was an ugly lump. It wasn't always that way, however. Originally, the structure at 100 Fillmore Street was a swank, modernist landmark housing a branch of the now-defunct Neustseter's department store; in the 1970s, when mid-century modern was out of style, the chic curtain walls were stripped off and replaced by aggregate. But now, in its reincarnation as Pura Vida, a glitzy gym and spa, the building has recaptured its lost glory, clad in a neo-modernist vocabulary of details, including huge wraparound windows on the upper floors. The spa is owned by a partnership including J. Madden, son of big-time developer John Madden. But it was the work of developer the Sturm Realty Group and the good folks at Gensler ? notably Blake Mourer ? and Semple Brown Design that turned this sow's ear into the best silk purse in Cherry Creek.