Siri’s spirit and originality did not disappoint. From its earliest days, architects and passersby alike were intrigued by surprises in the buildings' construction. Rising dramatically from the shore of the historic Potomac River, two distinct structures dominated the triangular block of land: a circular council chamber and an 11-story crescent-shaped secretariat. By December 1964, texture and pattern had begun to emerge, giving each building a distinct character. Geometric diamond shapes decorated the outside of the council chamber, visually played off against the elegant vertical lines of the larger secretariat building. Gradually, other elements were added: reflecting pools, white columns, and slim concrete fins that gave the buildings a soaring quality. 