Interesting trivia about building Xi'an City Wall

When we talk about the civilization of a city, we naturally associate it with its featured buildings. In Xi'an, the city wall is absolutely the representative site.

Xi'an City Wall is the largest, best preserved and oldest surviving ancient city wall in China, with a total length of 13.74 kilometers, a height of 12 meters and a top width of 12-14 meters. According to experts' calculations, the total number of bricks used for the entire wall is over 26 million. If the city wall had been built with modern red bricks, at least 200 million bricks would have been used.

But here comes the question, how did the ancient people complete such a gigantic project when there were no modern construction machines? 

How was the city wall reinforced?

At that time, the entire wall was rammed layer by layer with pure yellow earth and a small amount of lime.

In order to tamp down the rammed earth, the ancient people added wood studs to the inside, just like we add steel rebar in industrial concrete today.

During the Ming and Qing Dynasties, based on the existing Sui and Tang imperial walls, the workers carried out expansion and repairment, adding large stone bars at the bottom.

"The vertical+horizontal brick layout"

It takes an enormous number of bricks to build up the city wall. While the ancient workers laid the bricks on the outside, the bricks were laid out in a unique way: one put horizontally, one put vertically, and so on. This way, the entire wall was built up with a pretty solid structure, and the bricks were jointed closely.

How did the ancient people "glue" the bricks together?

In the days when there was no cement, the ancient people smartly used lime with glutinous rice juice as the binder, which comes with great stickiness. With this strong "glue", the bricks of the city wall are still closely jointed together today, even though they have lasted for almost 500 years.

Automated Monitoring Platform of Xi'an City Wall

With the progress of technology and continuous exploration and practice, combined with the heritage protection experience of previous generations, Xi'an City Wall is now equipped with a scientific, standardized and institutionalized preventive protection system, which has solidified the security foundation for this valuable cultural heritage.