Title: Tang dynasty
Content:  became the political center of the empire and served as the royal residence of the Tang emperors for more than 220 years.  The Tang capital was the largest city in the world at its time, the population of the city wards and its suburban countryside reaching two million inhabitants. The Tang capital was very cosmopolitan, with ethnicities of Persia, Central Asia, Japan, Korea, Vietnam, Tibet, India, and many other places living within. Naturally, with this plethora of different ethnicities living in Chang'an, there were also many different practiced religions, such as Buddhism, Nestorian Christianity, and Zoroastrianism, among others. With the open access to China that the Silk Road 
Title: Tang dynasty
Content:   Although Chang'an was the capital of the earlier Han and Jin dynasties, after subsequent destruction in warfare, it was the Sui dynasty model that comprised the Tang era capital. The roughly square dimensions of the city had six miles (10 km) of outer walls running east to west, and more than five miles (8 km) of outer walls running north to south. The royal palace, the Taiji Palace, stood north of the city's central axis. From the large Mingde Gates located mid-center of the main southern wall, a wide city avenue stretched from there all the way north to the central administrative city, behind which was the Chentian 
Title: Tang dynasty
Content:  dynasty issued an edict which forced Uighurs in the capital, Chang'an, to wear their ethnic dress, stopped them from marrying Chinese females, and banned them from passing off as Chinese. Chang'an was the center of the central government, the home of the imperial family, and was filled with splendor and wealth. However, incidentally it was not the economic hub during the Tang dynasty. The city of Yangzhou along the Grand Canal and close to the Yangtze River was the greatest economic center during the Tang era. Yangzhou was the headquarters for the Tang government's salt monopoly, and was the greatest industrial center of China. It acted as 
Title: Tang dynasty art
Content:   Tang dynasty art is Chinese art made during the Tang dynasty (618–907). The period saw great achievements in many forms—painting, sculpture, calligraphy, music, dance and literature. The Tang dynasty, with its capital at Chang'an (today's Xi'an), the most populous city in the world at the time, is regarded by historians as a high point in Chinese civilization—equal, or even superior, to the Han period. The Tang period was considered the golden age of literature and art. In several areas developments during the Tang set the direction for many centuries to come. This was especially so in pottery, with glazed plain wares in 
Title: Taiyuan
Content:  In 618, Li Yuan founded Tang dynasty, which is generally considered a golden age of Chinese civilization. Taiyuan expanded significantly during the Tang dynasty, partly because Taiyuan was the military base of the founding emperors Li Yuan and Li Shimin. As Li Shimin wrote in 619: "Taiyuan, the base of the imperial regime and the foundation of the state."  In 690, Wu Zetian set Taiyuan as the Northern Capital,, one of the three capitals, along with Chang'an and Luoyang, as depicted in the poem by : "The king of the heaven has three capitals, the Northern capital is one of them." (""). In 742 AD, Emperor Xuanzong of Tang changed its name further to Beijing. During Tang Dynasty, the title Northern Capital to Taiyuan had been endowed or abolished multiple times.
Title: Chang'an
Content:  Both Sui and Tang empires occupied the same location. In 582, Emperor Wen of the Sui dynasty sited a new region southeast of the much ruined Han Dynasty Chang'an to build his new capital, which he called Daxing (大興, “Great Prosperity”). Daxing was renamed Chang'an in the year 618 when the Duke of Tang, Li Yuan, proclaimed himself the Emperor Gaozu of Tang. Chang'an during the Tang dynasty (618–907) was, along with Constantinople (Istanbul) and Baghdad, one of the largest cities in the world. It was a cosmopolitan urban center with considerable foreign populations from other parts of Asia and beyond. This new Chang'an was laid 
Title: Tang Dynasty City
Content:  The Tang Dynasty City, formerly Tang Dynasty Village, was a theme park once located at 2 Yuan Ching Road in Jurong, Singapore.
Title: History of China
Content:  The Tang dynasty was a golden age of Chinese civilization, a prosperous, stable, and creative period with significant developments in culture, art, literature, particularly poetry, and technology. Buddhism became the predominant religion for the common people. Chang'an (modern Xi'an), the national capital, was the largest city in the world during its time. The first emperor, Emperor Gaozu, came to the throne on 18 June 618, placed there by his son, Li Shimin, who became the second emperor, Taizong, one of the greatest emperors in Chinese history. Combined military conquests and diplomatic maneuvers reduced threats from Central Asian tribes, extended the border, and brought neighboring states into a tributary system. Military 
Title: Tang of Shang
Content:  Tang's reign was regarded as a good one by the Chinese. He lowered taxes and the conscription rate of soldiers. His influence spread to the Yellow River, and many outlying tribes, such as Di and Qiang, became vassal states. He also established Anyang as the new capital of China. According to the Bamboo Annals, Tang built a palace called Xia She (夏社) to memorialize the Xia dynasty. In the first five years of his reign, there were several droughts. Tang ordered golden coins to be made and distributed to poor families who had been forced to sell their children because of the drought. It was intended for them to use this money to buy their children back. According to the Bamboo Annals, in the 9th year of his reign, he moved the Nine Tripod Cauldrons, made by Yu the Great, to the Shang Palace.
Title: Tang Xiujing
Content:  Zetian had Wei and Tang investigate, but before investigations could be complete, there were reports that Khitan and Xi were set to attack the northeastern border, and she gave Tang the additional titles as the commandant of You and Ying Prefectures (headquartered in modern Beijing) and protectorate general of Andong to defend against Khitan and Xi. Before Tang was set to depart the capital Luoyang, he secretly spoke with Li Xian, stating, "The two Zhangs depend too much on the favors of the emperor and have lost their proper places as subjects. Surely a disturbance will come.  Your Royal Highness should be careful."

Question: What is the capital of Tang Empire?
Answer: Chang'an.
Changan.
Chang An.