Like most people, I'd never seen a project by Christo and Jeanne-Claude before, even though the two have been transfiguring outside environments with fabric—and sometimes with objects, like the forests of umbrellas created on the coasts of California and Japan—since the late '60s. The pair's adventures are mostly witnessed second-hand: The projects have a brief life, and those who do see them often can't take in the whole thing. Christo immodestly, but accurately, calls them "legends." A reddish-orange curtain hung over a valley, if you haven't seen it, sounds like a horse with wings. If you have seen it, it must be something like putting a skirt on nature. To experience the work live (or in film) is to realize that everything this pair does has at least two facets: Their art is both a conceptual challenge to appearance and a sensual disorientation of reality. Just as they soften hardhearted politicians, Christo and Jeanne-Claude feminize hard physical realities.