Architectural history is sometimes recounted as if it evolved autonomously, architects attacking and solving architectural problems largely of their own devising. But because buildings are large, complicated, and expensive, architecture is subject—more than other arts—to outside forces, economic, political, social. Here’s a historical counterfactual. What if the Depression and the Second World War hadn’t happened? What if construction hadn’t been halted for more than a decade and the American modernist movement of the Twenties and Thirties that produced the Empire State Building and Rockefeller Center, the Folger Shakespeare Library and  the Walter Reed Naval Medical Center, Omaha’s Union Station and Los Angeles City Hall, had not abruptly been halted but had blossomed further instead? What if Mies van der Rohe and Walter Gropius had stayed in Germany, and remained avant-garde outsiders, entering competitions rather than building? The story of architecture would have taken a very different turn.

Photo: Union Station, Omaha. Gilbert Stanley Underwood, arch. (1931)