Nearly one third of the Great Wall of China has disappeared due to natural erosion, destruction by humans and a lack of protection, Beijing Times reports.

A research conducted by the China Great Wall Society last year shows that only around 8% of the Great Wall built in Ming dynasty, the most visible section of the Great Wall today, are well-preserved.

The rainy season in Beijing and its neighboring Hebei province has led to the erosion of ramparts and part of the wall. Trees and grass growing in the cracks of the wall have also led to the risks of collapse.

Meanwhile, human destruction, illegal trade or the practice of stealing bricks from the Great Wall have threated the conservation of this UNESCO world heritage.

Some special bricks used on the Great Wall that have caved Chinese characters are being sold by local villagers, who live close to the wall.

The increasing number of tourists who explore parts of the Great Wall that have not been repaired have also led to its destruction.

Some local governments only protect and repair a short section of the Great Wall, its most symbolic part or the part that attracts most visitors and brings economic benefits.

But a major part of the Great Wall, in areas that have not been turned into tourist spots, are in a derelict condition.

Dong Yaohui, vice chairman of the China Great Wall Society, says that the grandness and length of the Great Wall made the architecture a magnificent world cultural heritage, so the repair and protection work should be extended to encompass the entire Great Wall, rather than only a section of it.