With over 600 years of history, Beijing’s Forbidden City was the royal palace during the Ming and Qing dynasties. This is the largest royal palace in the world preserved almost intact to this day. Architecture of the Forbidden City is divided into two main areas: pre-tide and harem. Stretching over an area of ​​720,000 m2, this work includes 9,999 rooms. Interestingly, many visitors find that the roof in the Forbidden City is always clean, even though it is not cleaned regularly. This makes many people curious why it is so. According to experts, due to the large number of internal architectures inside the Forbidden City, cleaning and cleaning the roof is not easy. In addition, the Forbidden City is an ancient architectural work of hundreds of years old, so people cannot clean and clean by themselves like other works. The roof of the Forbidden City is not covered with dirt or contaminated with bird droppings. This stems from the architecture of the buildings. Specifically, the entire roof in the Forbidden City is painted with gold. This color not only represents luxury and splendor of the royal family, but also represents the destiny of Tho. The Chinese in feudalism thought that land was the source of all things. Therefore, yellow is used as the main color in the Forbidden City. In addition, the yellow color of the roof will contrast with the blue of the sky. When birds fly over the roof area, they will be blurred, limiting their ability to observe. Therefore, very few birds move or land on the roof of the Forbidden City. As a result, there is not much bird droppings on the roof. In addition, the ancients used glazed tiles to make dust and bird droppings easy to wash away when it rains. The curved roof design of the buildings in the Forbidden City contributes an important part in keeping this ancient building clean. Invite readers to watch the video: The US and China tense in high-level dialogue. Source: VTV24.