China's ultramarathon tragedy
When Zhang Xiaotao woke up he was in a cave and somebody had lit a fire to keep him warm. He had no idea how he'd got there.
Zhang's frozen unconscious body had been found by a passing shepherd who'd wrapped him in a quilt and carried him over his shoulders to safety. He was one of the lucky ones.
In May this year, 21 competitors died at an ultra-running event in northern China hit by extreme weather conditions: hail, heavy rain and intense gales caused temperatures to plummet, and nobody seemed prepared for it.
Only a small number felt comfortable talking about what happened - and some have been threatened for doing so.