Xi'an City Wall was originally built in the Tang Dynasty (618-907), later to be expanded and fortified in  the Ming Dynasty(1368-1644). It is one of history's oldest surviving military defense systems, as well being one of the largest ancient military defensive systems in the world.

When Zhu Yuanzhang, the first Emperor of the Ming Dynasty (1368-1644), captured Huizhou, a hermit named Zhu Sheng admonished him that he should 'built high walls, store abundant food supplies and take time to be an Emperor,' so that he could fortify the city and unify the other states. After the establishment of the Ming dynasty, Zhu Yuanzhang followed his advice and began to enlarge the wall built initially during the old Tang Dynasty (618 - 907), forming today's scale of Xian City Wall.

 After the enlargement, the city wall stands 12 meters (40 feet), 12-14 meters (40-46 feet) across the top, 15-18 meters (50-60 feet) thick at bottom and 13.7 kilometers (8.5 miles) in length with deep moats surrounding it. It boasts the most complete city wall to have survived through China's long history.
Initially, the city wall was built with layers of dirt, with the base layer including also lime and glutinous rice extract. Throughout the time the wall has been restored three times. In 1568, Zhang Zhi (the government officer of that period) was in charge to rebuild the wall with bricks. In 1781, another officer, Bi Yuan, refitted the wall and the gate towers. More recently (since 1983) the Shaanxi Provincial Government restored the wall again. The circular City Wall Park has been built along the high wall and the deep moat. The thriving trees and flowers decorate the classical Chinese architecture of the wall, adding additional beauty to the city of Xian.

The wall was built of earth, rammed layer upon layer during the early time. The base layer was made of earth, quick lime, and glutinous rice extract, tempered together. This made the wall extremely strong and firm. Later, the wall was totally enclosed with bricks. The Ming City wall encircles the city in a rectangle with one gate on each side. On the wall, fortifications such as watch towers, ramparts, (duo-kou) were built into a complex and well-organized system of defense.
There are total 98 ramparts on the wall and there are 120 meters distance from each other- towers that extruding out from the main wall. On the top of the rampart were 5984 2-metre- (7-foot-) high crenels called duo-kou. On the upper part of the duo-kou were large openings used to watch and shoot at attackers, and on the lower part were small openings, or loopholes, through which defenders could also shoot.
The distance between ramparts is just within the range of arrow shot from either side, which allowed soldiers to protect the entire wall without exposing themselves to the enemy. Every several rampart on the wall has a sentry building of two or three stories where soldiers were stationed.
 

Cycling on the Xian City Wall
Try biking on the Wall, you will have an enjoyable and interesting experience. To cycle round the wall for a whole circle takes 1.5 to 2 hours at a medium speed. The bicycle deposit is CNY 200. The single bicycle costs CNY 45/2 hours. The tandem bicycle costs CNY 90/2 hours.
You will have to pay an extra charge if you cycle more than two hours. An extra 10 minutes costs CNY 5 for a bicycle, and CNY 10 for a tandem bicycle. Bicycles should be returned at the South Gate before 20:00 if you don't return them before 18:00 at the other three gates.
Sightseeing battery car:
The ordinary sightseeing battery car costs CNY 80 for a circle ride while the luxurious one costs CNY 120. One can also visit the wall by sections. The ordinary type costs CNY 20 between two stops. The luxurious type costs CNY 30.
Route: South Gate – West Gate – North Gate – East Gate

Travel Tips
Add:  City Wall Park, Xian City,Shaanxi Province
Admission Fee: CNY 60
Opening Hours: 08:00-20:00

Transportation:
To the South Gate: Take subway line 2 to Yongningmen Station; bus no.6, 11, 12, 23, 46, 215, 239, 600, 603, 608, 713, 910, K600, K618, or Wulong Special Line…and arrive at South Gate Station.
To the East Gate: Take bus no.8, 22, 27, 29, 33, 37, 43, 45, 102, 203, 218, 235, 252, 300, 527, 602, 604, 714, or 903…and arrive at East Gate Station.
To the North Gate: Take subway line 2 to Anyuanmen Station; bus no.6, 26, 28, 33, 37, 39, 117, 205, 206, 208, 214, 229, 236, 238, 336, 506 or 511…and arrive at North Gate Station.
To the West Gate: Take bus no.4, 10, 15, 23, 31, 201, 205, 206, 215, 221, 222, 223, 300, 407, 504, 611 or 701…and arrive at West Gate Station.