The ribbon of brown water cutting swiftly through the gorge below is rich with snowmelt. With few cars passing, its echoing sound fills the air. In the distance, the Hengduan mountains slump under their snowpack as if crumpled beneath its weight. Mr Guo recalls the drivers who have taken a switchback too quickly and fallen to their deaths in the valley below. He tells of workers who lost their footing or whose harnesses failed while building a bridge near his home town of Cizhong, 20 or 30 kilometres south. He pulls hard on his cigarette. “This river”, he says, “has taken so many lives.”