The new conservatory of the Denver Botanic Gardens in Colorado represents a marriage of two contrasting architectural materials: massive reinforced concrete and clear, lightweight acrylic plastic. The conservatory consists of a series of gracefully openings covered with skylights formed from sheets of clear thermo-plastic. The conservatory is 51 feet high, 160 feet long and 72 feet wide. At all points in the design of the conservatory, glazing shared center stage with concrete. This glazing question was complicated by the fact that it was essential to the character of the building that the exterior surface of the concrete be left exposed. This meant that the glazing supports would have to be hidden for view within the depths of the arches. This posed a problem since the open diamonds formed by the interlacing arches were quite large- ranging from 8 feet by 8 feet at the top of the conservatory to 8 feet by 18 feet in the lower diamonds. The glazing problem was solved by using large pyramidal skylights of clear acrylic plastic. The architects chose this material because, in addition to its light transmitting properties and breakage resistance, it can be economically shaped and trimmed after forming.