The huge Chang Tomb (Ling means tomb) is the final resting place of the third Ming Emperor, Zhu Di. He named his ruling era Yongle (eternal joy) and was hence known as Emperor Yongle. He ruled China from 1402 to 1422. The construction of the tomb started in the seventh year of his reign and took five years to be completed. The layout of Chang Ling follows the pattern of Xiao Ling Mausoleum in Nanjing, tomb of the first Ming Emperor. Structures proceeding along the central axis are: the Front Gate to the tomb, the Gate of Eminent Favor, the Hall of Eminent Favor, the Dragon and the Phoenix Gate, Soul Tower and the Wall-Encircled Earth Mound, of which the Hall of Eminent Favor is the most impressive and important. The hall covers 1,956 square meters, nearly the same as of the Hall of Supreme Harmony in the Forbidden City, but it exceeds the latter architecturally as all the columns, beams, etc. are made of nanmu, a durable high quality softwood. The 32 huge 12.58 meter-tall pillars of the hall are each made from a single nanmu tree trunk. This valuable timber came from Sichuan, Hubei, Henan and Jiangxi provinces, all thousands of kilometers away from Beijing. It is said that it took about five years just to transport these enormous treetrunks. This scale of historic project is rarely seen in other parts of the world. The hall is the largest and most magnificent structure of nanmu wood still existing in China. This hall has becomes the exhibition hall for the historical relics unearthed from Chang Ling.