Constructed in the early 15th century, the Temple of Heaven is a collection of some of the most important Taoist temples and other related structures in China. Known also as the Altar of Heaven, these temples were a sacred place of prayer for emperors of the Qing and Ming dynasties, and today are well-maintained reminders of the continued strength of Taoism in Chinese society. Other important structures include the Hall of Prayer for Good Harvests, the Imperial Vault of Heaven, and the Circular Mound Altar. The design of the buildings is ancient Chinese architecture at its best and is full of symbolism representing the natural elements, as well as a motif of 9's, the emperor's number. Southeast of city center, entrance to the Temple of Heaven costs anywhere from 10-35Y ($1.50- $5.50 US), depending on when you visit.