What is one threat that is damaging the Great Wall of China?

It should be the pollution caused by human beings. As it is becoming more and more populat throughout the world, more and more tourists go to wall; however, the amount of trash or garbage become the severest problem. This is just personal throught for your reference!

As the most important factor I can say natural disaster, climate changes and erosion can make serious threat to the wall that undoubtedly human being will be the superior among these threats.

some people are stealing bricks from the wall. Also people are throwing trash on the wall and it is hurting the wall. Some people might think i am dumb for saying they can STEAL bricks from the strong wall but they can cut them out with special tools. Just personal thought!