"A survey of textbooks reveals that Le Corbusier was the greatest architect of the twentieth century, followed by Frank Lloyd Wright and Ludwig Mies van der Rohe. The same evidence shows that the greatest architects alive today are Frank Gehry and Renzo Piano. Scholars have long been aware of the differing approaches of architects who have embraced geometry and those who have been inspired by nature, but they have never compared the life cycles of these two groups. The present study demonstrates that, as in other arts, conceptual architects have made their greatest innovations early in their careers, whereas experimental architects have done their most important work late in their lives. Remarkably, the experimentalists Le Corbusier and Frank Gehry designed their greatest buildings after the age of 60, and Frank Lloyd Wright designed his after 70"--National Bureau of Economic Research web site.