Xi'an Palace, the Imperial City, and the civilian section, with a total area of 84 km² within the city walls. At the time, it was the largest city in the world. The city was renamed Chang'an in the Tang Dynasty. In the mid-7th century, after returning from his pilgrimage to India, Buddhist monk Xuan Zang (popularly known as Tang Sanzang) established a translation centre for Sanskrit scriptures.
Construction of the Great Wild Goose Pagoda began in 652. This pagoda was 64 m (209.97 ft) in height, and was built to store the translations of Buddhist sutras obtained from India by the Xuan Zang. In 707, construction of the Small Wild Goose Pagoda began, and measured 45 m (147.64 ft) tall at the time of completion. The massive 1556 Shaanxi earthquake eventually damaged the tower and reduced its height to 43.4 m (142.39 ft).
Chang'an was devastated at the end of the Tang Dynasty in 904. Residents were forced to move to the new capital city in Luoyang. Only a small area in the city continued to be occupied thereafter. During the Ming Dynasty, a new wall was constructed in 1370 and remains intact to this day. The wall measures 11.9 km in circumference, 12 m (39.37 ft) in height, and 15–18 m (49.21–59.06 ft) in thickness at the base; a moat was also built outside the walls. The new wall and moat would protect a much smaller city of 12 km².
In October 1911, during the revolution in which the Qing Dynasty was overthrown, the Manchus living in the north-eastern zone within the city walls were massacred. In 1936, the Xi'an Incident took place inside the city during the Chinese Civil War. The incident brought the Kuomintang (KMT) and Communist Party of China to a truce to in order to concentrate on fighting against the Japanese Invasion.
On May 4, 2010, a new metro tunnel started in Xi’an, which will ease the move for commuter travel from surface streets to below ground
