I worked with a young man that did this stuff. He crashed on his last ride and woke up days later in the hospital. His mom showed him a video of her burning his skateboards. He had to wear an eye patch for months because of severe crosseyedness. His eyeballs got rotated in his eye sockets.
Danny MacAskill can go ANYWHERE on his bicycle. He rides the tops of fences, flips his bike over barbed wire fences, etc.