Great Wall of China
Chinese and foreign toursits walk on a section of the Great Wall of China on October 28, 2014 in Mutianyu, near Beijing, China.Getty Images

China's Great Wall, the world's longest human construction, is slowly giving away to natural and human-driven deterioration.

The UNESCO World Heritage site that some claim is visible from space spans across some 9,000 to 21,000kms from Shanhaiguan to Jiayuguan in China.

Over the years, the bricks have been stolen in some areas by residents who used them to build houses.

Villagers in the Lulong county in the northern province of Hebei allegedly knocked off thick grey bricks and some slabs containing Chinese engravings.

The slabs were later sold for some 30 yuan (£3) each, reported AFP News.

Despite facing a fine of up to 5,000 yuan (£512) under Chinese regulations, "there is no specific organisation to enforce the rules," said Jia Hailin, a cultural relics protection official in Hebei.

"Damage could only be reported to higher authorities and it is hard to solve when it happened on the border of two provinces."

Approximately 1,962 kilometres of the wall has reportedly deteriorated over the years.

"Even though some of the walls are built of bricks and stones, they cannot withstand the perennial exposure to wind and rain," the Beijing Times quoted Dong Yaohui, a vice president of the Great Wall of China Society.

"Many towers are becoming increasingly shaky and may collapse in a single rain storm in summer."

In particular, the undeveloped parts of the Great Wall have seen more people than it could take causing severe damage.

In 2014, a Channel 4 documentary revealed the Great Wall of China is a series of overlapping fortifications held together with sticky rice.

"Analytical study shows that the ancient masonry mortar is a kind of special organic-inorganic composite material. The inorganic component is calcium carbonate, and the organic component is amylopectin, which comes from the sticky rice soup added to the mortar," read a research finding led by Bingjian Zhang from the Zhejiang University in Hangzhou.