woven wooden strips or sorghum stems fastened to the beams. The most decorative and the most complex ceiling was the caisson. Sanqing Hall (Hall of the Three Purities) is a Yuan period structure with "three" zaojing in its ceiling. A zaojing is a wooden dome over an imperial throne or statue in Chinese architecture. As the caisson became increasingly standard in formal architecture in ancient China, similar structures also appeared in Buddhist grottos, such as in Dunhuang. Cultural significance Caissons were highly decorative and only included in important or highly decorated buildings. They had no specific cultural significance, since in structure they were equal to cupolas and domes constructed around the world. However the rich ornamentation often conveyed cultural significance in the themes chosen and in display within the caissons. See also Chinese architecture Forbidden City Notes External links Baoguo Temple - Dougong and caisson structures A collection of caisson images at Fotoe.com Architecture in China Chinese architectural history Ceilings Traditional Chinese architecture