Xi'an is more than 3,000 years old and was known as Chang'an in ancient times. For 1,000 years, the city was the capital for 13 dynasties, and a total of 73 emperors ruled here. Xi'an is the undisputed root of Chinese civilization having served as the capital city for the Zhou, Qin, Han, and Tang dynasties. With so much history within the ground the city lies upon, it is no wonder that there are so many historical ruins, museums and cultural relics to be found here. It was already influencing the world outside of the Great Wall of China as the eastern terminus of the Silk Road（丝绸之路).