Unity Temple (1905, Oak Park, Illinois)
Unity Temple is Frank Lloyd Wright’s only surviving public building from his Prairie period. Limited by a modest budget and an urban site, Wright created a bold design and used unconventional materials to produce a groundbreaking building. Constructed of exposed, poured-in-place reinforced concrete, Unity Temple was one of the earliest uses of the low-cost, revolutionary new material in a public, non-industrial building. While the unpainted concrete exterior is presented as a solid cubic mass, the interior is its opposite—spaces are floating, colored planes held together by lighting from above. Today, its auditorium/worship space is still used for religious services, performance, assembly and as a meeting hall.