Changling is located at the foot of Heavenly Longevity Hill. It is the tomb for the 3rd Ming Emperor Zhudi and his wife Empress Xu. Changling is the first, largest and also the best-preserved tomb of the 13 Ming Tombs. Construction of it started from 1409. It took 18 years and was completed in 1427. The layout of Changling just followed the example of Xiaoling in Nanjing, the tomb for the first Ming Emperor Zhu Yuanzhang. Structures along the central axis are: the Front Gate to the tomb, the Gate of Eminent Favor, the Hall of Eminent Favor, the Dragon and Phoenix Gate, Soul Tower and the wall-encircled Earth Mound. The design of Changling is square in the front and round at the back, reflecting the ancient Chinese belief that Heaven is round and the Earth is square. The Gate of Eminent Favor and the Hall of Eminent Favor of Changling on the central axis are still standing today. That is why Changling is considered to be the best-preserved tomb of the 13 Ming Tombs.