[In mid-2000s], his urban work has begun to seem increasingly quixotic. In a 2001 development plan for Harvard University, which was expanding across the Charles River into nearby Allston, Koolhaas proposed diverting the path of the river several miles to create a more unified campus. The idea seemed preposterous, and Harvard’s board quickly rejected it, but it carried a hidden message: America’s astonishing growth during the first three-quarters of the 20th century was built largely on the hubris of its engineers. (Think of the Los Angeles depicted in Roman Polanski’s Chinatown, a city that diverted water across 250 miles of desert to feed the growth of the San Fernando Valley.) Why, Koolhaas seemed to be asking, aren’t such miracles possible today?

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The countryside has become “more volatile than the accelerated city,” Koolhaas writes in one of the mock-ups. “A world formerly dictated by the seasons is now a toxic mix of genetic experiment, industrial nostalgia [and] seasonal immigration.”

It’s hard to know whether you regard this as nightmare or opportunity, I tell him. “That has been my entire life story,” Koolhaas said, “Running against the current and running with the current. Sometimes running with the current is underestimated. The acceptance of certain realities doesn’t preclude idealism. It can lead to certain breakthroughs.” In fact Koolhaas’ urbanism, one could say, exists at the tipping point between the world as it is and the world as we imagine it.