Asked about the consequences of the French Revolution, Chou En-lai replied, 'It's too soon to tell.' That's the response that comes to mind when pondering the significance of the great Land Art projects of the late 1960s and 1970s. With their megalomaniacal schemes and gargantuan undertakings—some, like James Turrell's Roden Crater in Arizona, or Michael Heizer's City in Nevada, still uncompleted after more than forty years—these artists were thinking big, not just in size and space but in time. If they succeed, the best of their undertakings have more in common with sacred or prehistoric sites than with the rival claims and fads of contemporary art. The art stuff provides an immediate context, but it is more revealing to take a different and longer perspective.