What is the color of the glazed tiles on top of the Temple of Heaven

The top of the Temple of Heaven Prayer Hall is covered with blue glazed tiles, because the sky is blue, as a symbol of the sky. It indicates that one does not dare to claim respect before heaven.

Reason:

Since the emperor claimed to be the son of heaven, "God" residence naturally larger than the "son of heaven", so the altar of heaven covers an area twice as large as the Forbidden City. Probably out of the same scruples, the main building of the Temple of Heaven to dark blue glazed tiles on the top, do not dare to overstep the use of the Royal Garden is dedicated to the bright yellow glaze, and each year before the start of the ceremony of the Emperor to the east side of the DanHei Bridge dedicated to the service platform temporarily will be yellow robes to blue robes to the heavenly demonstration of his pious reverence and worship.