Ancient Chinese Astronomers believed that the Purple Star (Polaris) was in the center of heaven and the Heavenly Emperor lived in the Purple Palace. The Palace for the emperor on earth was so called the Purple City. It was forbidden to enter without special permission of the emperor. Hence its name ‘The Purple Forbidden City’, usually ‘The Forbidden City’, which is surrounded by looped city wall and moat.
This photo was taken after a strong storm at time of sunset on July 21, 2014 for the northeast watchtower of the Forbidden City.