The unique spiral building designed by Frank Lloyd Wright—reluctantly, since he thought New York was too overbuilt—tends to overshadow the collections within. Designed as a reverse version of a Babylonian temple, the Guggenheim completely changed museum-going, sending visitors to the top floor first and then allowing them to wind their way down along a corkscrew ramp. What they see as they go are special exhibitions, like the 2008 installation by Cai Guo-Qiang that saw cars suspended from the central atrium—an exhibition described by Guggenheim director Thomas Krens as one of the "best artistic transformations of the Frank Lloyd Wright space we've ever seen." There are also rooms devoted to selections from the Guggenheim Foundation's eclectic collection, including sculptures by Brancusi and Arp and paintings by Picasso, Pissarro, de Kooning, Klee, and Jeff Koons. There are frequent traveling exhibitions, and since the museum has outposts in other cities such as Bilbao and Venice, pieces may circulate from other locations.