I finally got to see 'The Guggenheim' this summer. The Solomon R Guggenheim Museum to give it it's correct name, Frank Lloyd Wright's masterpiece. Wright's original concept was to use red stone cladding, this was substituted with white concrete render to cut costs.
It was a lot smaller than I expected and the location deprives the visitor of stepping fully back to experience the building as a whole. Maybe one day the surrounding buildings will be demolished but given Manhattan land prices I doubt it.
Much of the museum was closed for renovation when we visited but I was happy just to see and photograph it from the outside. And to visit the shop of course!