This document provides information about the Temple of Heaven in Beijing, China. It discusses the Imperial Sacrificial Altar (Qi Nian Dian) located within the Temple of Heaven. The Qi Nian Dian was first constructed in 1420 during the Ming Dynasty and has since been extended and renovated. It is the largest altar in the Temple of Heaven and was used by Ming and Qing emperors for worshipping heaven. The document describes the structure, layout, ornamentation, materials used and feng shui symbolism of the Qi Nian Dian.