Title: Xi'an
Content:  Xi'an (, ;     ; Chinese: ), alternately romanized as Sian, is the capital of Shaanxi Province. A sub-provincial city on the Guanzhong Plain in Northwest China, it is one of the oldest cities in China, the oldest prefecture capital and one of the Chinese Four Great Ancient Capitals, having held the position under several of the most important dynasties in Chinese history, including Western Zhou, Qin, Western Han, Sui, Northern Zhou and Tang. The city is the starting point of the Silk Road and home to the UNESCO World Heritage set Terracotta Army of Emperor Qin Shi Huang. Since the 
Title: West Triangle Economic Zone
Content:  Xi'an is the capital of Shaanxi province, and it has sub-provincial administrative status. Additionally, since ancient times, when it was known as Chang'an, it served as the capital of many dynasties. The mayor of Xi'an is Dong Jun, and the CPC Committee Secretary is Sun Qingyun.
Title: Xi'an
Content:  Xi'an lies on the Guanzhong Plain in the south-central part of Shaanxi province, on a flood plain created by the eight surrounding rivers and streams. The urban area of Xi'an is located at 34.26667°N, 108.93333°W. The city borders the northern foot of the Qin Mountains (Qinling) to the south, and the banks of the Wei River to the north. Hua Shan, one of the five sacred Taoist mountains, is located 100 km away to the east of the city. Not far to the north is the Loess Plateau. At the beginning of Han dynasty, Prime Minister Zhang Liang advised the emperor Liu Bang to choose Guanzhong as the capital of the Han dynasty: "Guanzhong Plain, which is located behind Xiao Pass and Hangu Pass, connects Long (Gansu) and Shu (Sichuan). Lands of thousand miles rich in harvest be found here, as if this place belongs to the nation of heaven." (关中左崤函，右陇蜀，沃野千里，此所谓金城千里，天府之国也) Since then, Guanzhong is also known as the 'Nation of the Heaven'.
Title: Xi'an
Content:  as part of the economic growth of inland China especially for the central and northwest regions, Xian has re-emerged as a cultural, industrial, political and educational centre of the entire central-northwest region, with many facilities for research and development, national security and space exploration. Xian currently holds sub-provincial status, administering 11 districts and 2 counties. The city is the third most populous city in Western China, the other two being Chongqing and Chengdu, as well as the most populous city in Northwestern China. In 2020, Xi'an was ranked as Beta- (global second-tier) city from the Globalization and World Cities Research 
Title: Shaanxi
Content:  Shaanxi (, Mandarin pronunciation: ; alternately Shensi) is a landlocked province of the People's Republic of China. Officially part of Northwest China, it borders the province-level divisions of Shanxi (NE, E), Henan (E), Hubei (SE), Chongqing (S), Sichuan (SW), Gansu (W), Ningxia (NW) and Inner Mongolia (N). Shaanxi covers an area of over 205000 sqkm with about 37 million people, the 16th highest in China. Xi'an &ndash; which includes the sites of the former Chinese capitals Fenghao and Chang'an &ndash; is the provincial capital as well as the largest city in Northwest China and also one of the oldest cities in China and the oldest of the Four Great Ancient Capitals, being the capital for the Western Zhou, Western Han, Jin, Sui and Tang dynasties. Xianyang, which served as the Qin 
Title: Chang'an District, Xi'an
Content:  Chang'an District is the second-most populous of 11 urban districts of the prefecture-level city of Xi'an, the capital of Shaanxi Province, in Northwest China. The district borders the prefecture-level cities of Shangluo to the southeast and Ankang to the southwest, Weiyang and Yanta Districts to the north, Baqiao District to the northeast, Lantian County to the east, and Huyi District to the west.
Title: Shaanxi
Content:  Shaanxi is considered one of the cradles of Chinese civilization. Thirteen feudal dynasties established their capitals in the province during a span of more than 1,100 years, from the Zhou dynasty to the Tang dynasty. The province's principal city and current capital, Xi'an, is one of the four great ancient capitals of China and is the eastern terminus of the Silk Road, which leads to Europe, the Arabian Peninsula and Africa. Under the Han dynasty, the Northern Silk Road was expanded to advance exploration and military purposes to the west. This Northern Silk Road is the northernmost of the Silk Roads and is about 2600 km in length. It connected the ancient Chinese capital of Xi'an to the west over the Wushao Ling Pass to Wuwei and emerging in Kashgar before linking to ancient Parthia. The Northern Song dynasty established 
Title: Xi'an
Content:  the Qing imperial post office, both of which were common until the general adoption of pinyin. The area of present-day Xi'an has been the site of several important former Chinese cities. The capital of the Western Zhou were the twin cities of Feng and Hao, known collectively as Fenghao, located on opposite banks of the Feng River at its confluence with the southern bank of the Wei in the western suburbs of present-day Xi'an. The Qin capital Xianyang was erected north of the Wei during the Warring States period and was succeeded by the Western Han capital of Chang'an, meaning "Perpetual 
Title: Xi'an
Content:   Xi'an became a cultural and political centre of China in the 11th century BC with the founding of the Zhou dynasty. The capital of Zhou was established in the twin settlements of Fengjing (丰京) and Haojing, together known as Fenghao, located southwest of contemporary Xi'an. The settlement was also known as Zōngzhōu (宗周) to indicate its role as the capital of the vassal states. In 738 BC, King Ping of Zhou moved the capital to Luoyang due to political unrest.
Title: Xianyang
Content:  Xianyang is a prefecture-level city in central Shaanxi province, situated on the Wei River a few kilometers upstream (west) from the provincial capital of Xi'an. Once the capital of the Qin dynasty, it is now integrated into the Xi'an metropolitan area, one of the main urban agglomerations in northwestern China, with more than 7.17 million inhabitants, its built-up area made of 2 urban districts (Qindu and Weicheng) was 945,420 inhabitants at the 2010 census. It has a total area of 10213 km2. Xianyang is home to the main campus of Northwest A&F University (NWAFU), one of the world's top universities in "Agriculture Science" related-fields and a member of "Project 985" club which is an organization of 39 reputable universities in China.

Question: What is Xi'an the capital of?
Answer: Shaanxi.