Unity Temple in Oak Park, Illinois, designed by Frank Lloyd Wright, became a landmark of early modern architecture through its bold reinforced concrete construction and rejection of traditional church forms. Built after the congregation’s earlier church was destroyed by fire in 1905, the complex combined a worship auditorium, Unity House, and a central entrance pavilion. Approved in 1906 and completed in stages through 1909, it featured abstract ornament, flat roof slabs, clerestory windows, and an interior centered on a pulpit within a Greek cross plan. Its influence on later architects was profound, and after restorations it remains one of Wright’s most important public works and a World Heritage Site.