Xi'an, called Chang'an and Haojing in ancient times, is the capital of Shaanxi Province, a megacity, a central city of the urban agglomeration of Guanzhong Plain, and an important base for scientific research, education, and industry in China. As of 2018, covering a total area of 10,752 km², including a built-up area of 700.27 km², the city had a permanent population of 10.0037 million, with the urban population reaching 7.4037 million or 74.01%. Xi'an is located in northwest China and central Guanzhong Plain and close to Weihe River in the north and Qinling Mountains in the south, with eight waterways passing by. It is one of the most important birthplaces of Chinese civilization and Chinese nation and the starting point of the Silk Road. More than a dozen dynasties made it the capital in ancient times. In 1981, the city was listed as a “world-famous historic city” by UNESCO by virtue of its abundance of historic sites, such as the Fenghao Capital, E-Pang Palace and Terra-Cotta Warriors of Qin, Weiyang Palace and Changle Palace of Han, Daxing City of Sui, Daming Palace and Xingqing Palace of Tang, which all together contribute to the “complex of Chang'an”. Xi’an is one of the best tourist destinations and the cities with the best international images in China. It has six sites of two projects included into the World Heritage List, including Mausoleum of the First Qin Emperor and the Terra-Cotta Warriors, Giant Wild Goose Pagoda, Small Wild Goose Pagoda, site of Daming Palace of Chang'an City of Tang, site of Weiyang Palace of Chang'an City of Han, and Xingjiao Temple Pagoda. Other famous tourist attractions include Xi'an City Wall, Zhonggu Tower, Huaqing Pond, Zhongnan Mountain, Datang Furong Garden, Shaanxi History Museum, Beilin, etc. Xi'an has 7 “double first-class” universities and colleges, including Xi'an Jiaotong University, Northwestern Polytechnical University, and Xidian University, amongst others. It was selected as one of the Happiest Cities in China on 25 November 2019.