Final answer:
The modern city on the site of the Mongols' Chinese capital is Beijing, where the Forbidden City, a symbol of traditional Chinese architecture, was constructed and served as the center of power.
Step-by-step explanation:
The modern city that stands on the site of the Mongols' Chinese capital is Beijing. After the Mongol Empire captured the Chinese city of Zhongxing Fu, the capital of the Xia state, the Mongols went on to rule much of China. The Yongle Emperor, later a ruler under the Ming Dynasty, moved the capital from Nanjing to Beijing. It was here that the construction of the new Forbidden City began, which served not only as the emperor's residence but also as the center of governmental power.
The Forbidden City represents the majesty and power of China during that era and is a symbol of traditional Chinese architecture. Beijing, as a directly controlled municipality, holds significant historical importance, being the site of successive capital cities throughout China's history, including the period of Mongol dominion.