The Great Wall of China, stretches more than 13,000 miles in its entirety. That length includes many branches, simple earth mounds and trenches, alongside the more iconic stone and brink construction. But according to surveys, just 8.2 percent of the Great Wall is in good condition, report Maggie Hiufu Wong and Serena Dong for CNN.

The sections most at risk, are those constructed during the Ming dynasty, which lasted from 1368 to 1644, and include some of the most famous stretches of the wall. The Beijing Times estimates that 30 percent of the Ming Dynasty wall has disappeared at the hands of erosion and human damage. For CNN, the reporters write:

And the situation could worsen, experts are warning, as not enough is being done to preserve what remains. "It's a great pity to witness the Great Wall in such devastated situation," Mei Jingtian, a volunteer who has worked for three decades to safeguard the structure and has founded of the Great Wall Protection Association, tells CNN.

Most tourists visit the restored section of the Ming wall, located north of Beijing. But the the increasingly popular practice of traveling to more remote stretches is causing trouble. Dong Yaohui, the deputy director of the Great Wall of China Society, tells CNN that locals sometimes take bricks from these remote sections with engravings in them to sell to tourists.

Weathering over the years has also taken its toll and Yaohui remarks that preserving and restoring the wall is a massive challenge. To save the historical treasure, the Chinese will need to come up with some creative solutions — already officials have set up a sacrificial zone for graffiti artists in an attempt to take pressure off the rest of the wall.