In a new special, John Portman - one of America's most daring and influential living architects - brings colleagues from his firm to visit Frank Lloyd Wright's Fallingwater in southwestern Pennsylvania, for an informal master class and case study. Together, the architects explore the commissioning, design and construction of the house, marvel at its distinctive architectural features, and ruminate about Wright's passion and vision. The architects speak candidly about their chosen field while contemporary and archival footage reveals the celebrated features of this iconic structure - its cantilevered design, covered walkways, numerous hearths, glass "corners" and natural building materials.