Huangyaguan

The Great Wall of China: when, how and which sections to visit - SilverKris

"Each May, this pass hosts a famously brutal marathon that draws several hundred runners to tackle one of the world’s toughest courses: competitors negotiate more than 20,000 stone steps of varying heights and cross uneven, rubble-strewn sections. The event, held in the Tianjin area, is an extreme-adventure draw for well-prepared runners (entry around US$200) and demands sturdy running shoes and serious conditioning." - Nicola Iseard