text: Unity Temple (1905-08, Oak Park, Illinois) represents a defining moment in Frank Lloyd Wright’s early career. Designed in Wright’s Oak Park Studio for his own Unitarian congregation, it is one of the first public buildings in America to feature exposed concrete and is Wright’s greatest public building of his Prairie era. The harmony of the building’s strikingly geometric architecture and decorative elements exemplifies Wright’s theory of organic design. Unity Temple announced a new era of innovation in modern architecture.