The world's smallest castle—Tuancheng Island

Address: West of Beihai North Gate, Xicheng District, Beijing Opening hours: 8:30–16:30 Tickets: 1 yuan Tuancheng Island is a green pearl inlaid between Beihai Park and Zhongnanhai, known as "the smallest castle in the world," with a history of more than 800 years. The city platform is 4.6 meters above ground level and covers an area of 4,553 square meters. During the Liao Dynasty, it was an island formed by the accumulation of mud in the lake. It was expanded in the Jin Dynasty, and a palace was built. In the Yuan Dynasty, it was enclosed by stone walls and renamed "Yingzhou." During the Ming Dynasty, the palace was rebuilt and renamed Chengguang Hall, and a city wall was built around the island. During the Qing Dynasty, Emperor Qianlong extensively expanded Tuancheng Island, forming its current layout. Enter from the east "Zhaojing Gate," go up the steps, and pass through the "Zhaomen" to reach Tuancheng Island. The central building is Chengguang Hall, with the Yu Weng Pavilion to the south and the Jingji Hall to the north, forming the central axis. On both sides, there are the Gulai Hall, Yuqingzhai, and the east and west side halls, symmetrically arranged, giving a sense of completeness despite its small size. There are three treasures here: the Jade Urn, the White Jade Buddha, and ancient trees. The Jade Urn, "Dushan Dayuhai," was made during the Mongol Empire, and legend has it that Kublai Khan used it to hold wine for banquets with his officials. The east and west side halls provide detailed explanations of the history and cultural background of the Jade Urn. The White Jade Buddha, enshrined in Chengguang Hall, is 1.5 meters high and carved from a single piece of white jade, flawless and pure. There is a noticeable knife mark on the left arm, a scar from the Eight-Nation Alliance in 1900. There are more than ten ancient trees over 300 years old, including the "Zheyin Hou" oil pine and the "White-robed General" white-bark pine, both over 800 years old, now tall and lush. The 270-meter-long city wall of this castle has no drainage outlets, and there are no drainage ditches on the ground. No matter how heavy the rain, the ground dries quickly after the rain. Where does the rainwater on Tuancheng Island go? Haha, interested friends can look up the rainwater drainage system of Tuancheng Island. The wisdom of the ancients is truly amazing.