claire watkins: of course.for having me. ♪ john: some see older buildings as revered artifacts that have stood the test of time. others see them as occupying sites that could be used for new development. ali rogin went to one place where that tension is playing out -- phoenix, which is a rich source of one specific style of architecture. ali rogin: in e valley of the sun, nature's gifts abound. so too do man-made treasures that help tell the story of postwar america. phoenix is a trove of mid-century modern architecture, style that mirrored the optimism of america after soldiers returned home from world war ii. designs focused on function, creative use of materials, and a connection to nature. alison king: it's what we call desert architecture. ali rogin: alison king is a professor of design history and runs modern phoenix, an archive and community for enthusiasts of mid-century modernism. why is phoenix such a hub for mid-century modern architecture? alison king: well, this really was the land of opportunity i