The Qing Dynasty military base located in the western suburbs of Beijing was built in 1748 by Emperor Qianlong. There used to be many structures, but now only a twin-tower compound, two pavilions and a stone fortress are still standing. For many years the military base and the buildings were shrouded in mystery. The twin-tower compound is still magnificent despite the ravages of time. The site is called the Round City because two big-roofed towers were built on the top of a thick fortified wall that encircled an openingSummer Pa, like a city wall. Unlike its two namesakes, one in Beihai Park and the other at the Summer Palace, this compound was not for imperial recreation, but for the emperors to view battle exercises by the elite Manchu troops. 

Entering the vaulted gate, you will find yourself in an arena-like opening about 40 metres in diameter. Flagstones form the floor of the arena which is flanked by two inner houses. It is not known for what they were used. There are two stairways leading to the top of the wall. The wall is damaged in places by tree roots that grew between the bricks and the stone slabs. The compound was used as a pigeon farm for many years before 1981. In fact, the whole Qing Dynasty military base was developed as a farm and between 1949 and 1981 was used to raise chickens, pigs, rabbits and pigeons. The damage to the site was enormous, but the visitor still can envisage its heyday through the inscriptions on two stone monuments. One is in the compound, the other in the pavilion. Written in the Manchurian, Chinese, Mongolian and Tibetan languages, the inscriptions tell why and how Manchu troops exercised here. One inscription says: 'In preparation for Jinchuan campaign, store fortresses were built at the foot of the Western Hills. Elite Manchu soldiers were selected to practise their scaling skills.' The fortresses were modeled after those used by rebels in mountainous Sichuan. In no more than a month, 2,000 soldiers mastered the assault skill, says the inscription. But the geographic barriers made the rebels unconquerable. To save the face of Manchu troops, the enemies were cajoled into surrender. Nevertheless Emperor Qianlong erected the monument to extol the triumph of the Marchu soldiers. He even renamed a temple there as the Temple of Triumph which was later destroyed During the reign of Qianlong (1736-1795), the Qing Dynasty knew its greatest prosperity and saw its fastest expansion. It incorporated Chinese Turkistan into its territory and renamed it Xinjiang. The monument inside the twin-tower compound records the military exploits of the Qing army in suppressing rebels in Xinjiang and conquering lli and Kashi, areas bordering Russia Qing Emperor Qianlong was a vainglorious ruler. He liked to boast about his 10 major victories. Even though some were won at a heavy price. 

Nowadays, many buildings at the base have vanished. There used to be nine fortresses but only one survived. 

West of the ruined Temple of Triumph is a place called the Little Garrison where prisoners captured from Sichuan were held. After more than 200 years, their descendants have been absorbed in the local population. The big field in front of the twin-tower compound used to be the main drilling ground. It is now an orchard. 

In 1981, the Beijing Cultural Relics Protection Bureau acquired the area as a new site for protection, and had invested an initial 500,000 yuan ($ 91,743) in its restoration. The Round City opened to the visitor in October 1989.