On June 13, 2009 (May 21, 2009 in the lunar calendar), the No. 1 pit of the Terracotta Warriors and Horses was excavated for the third time in 24 years. Qin Shi Huang's Mausoleum is located at the foot of Lishan Mountain, which is more than 30 kilometers east of Lintong County, Xi'an City. According to historical records, Qin Shi Huang Yingzheng began to build the cemetery when he ascended the throne at the age of 13. The planning and design of the cemetery was presided over by Prime Minister Li Si, and the general Zhang Han supervised the construction. The construction time was as long as 38 years. Qin Shi Huang's Terracotta Warriors and Horses Pit is the burial pit of Qin Shi Huang's Mausoleum, located 1,500 meters east of the cemetery. Qin Shi Huang's Terracotta Warriors and Horses burial pit sits west to east, and The earliest discovered is the No. 1 terracotta pit, which is rectangular, 230 meters long from east to west, 62 meters wide from north to south, and about 5 meters deep. It has a total area of 14,260 square meters. There are sloping doorways on all sides, and there is a terracotta warrior pit on the left and right sides. It is now called No. 2 pit and No. 3 pit. The terracotta pit has a reasonable layout and a peculiar structure. At the bottom of the pit about 5 meters deep, an east-west load-bearing wall is erected every 3 meters. The terracotta warriors are arranged in the gaps between the walls. In March 1974, when the villagers of Xiyang Village in the east of the mausoleum were drilling wells to resist drought, between Xiahe Village and Wula Village, three miles east of the mausoleum, a large-scale terracotta warrior pit of Qin Shi Huang Mausoleum was discovered. After excavation by archaeologists, the treasure of Qin Shi Huang Terracotta Warriors buried more than 2,000 years ago was uncovered. In 1975, the state decided to establish a museum on the original site of the terracotta pit. On October 1, 1979, the Qin Shi Huang Terracotta Warriors Museum began to exhibit to domestic and foreign visitors. On June 13, 2009, the No. 1 pit of Qin Shi Huang Mausoleum Terracotta Warriors and Horses was excavated again. Later, in the northern middle of the No. 1 pit, colorful terracotta warriors and horses Qin Shi Huang Terracotta Warriors and Horses Burial Pit, is the world's largest underground military museum.