CityCenter Las Vegas – 187 million square feet of floor space, 67 acres, $8.5 billion – includes buildings by Daniel Libeskind, Norman Foster, Cesar Pelli, Rafael Viñoly, Helmut Jahn, and Kohn Pedersen Fox, plus public artworks by Henry Moore, Frank Stella, Robert Rauschenberg, Claes Oldenburg and Maya Lin. How does it all work?