Hanging from a rope and bamboo ladder off a Himalayan mountain cliff, skilled Nepali climbers gather highly prized hallucinogenic honey -- an ancient tradition stung by environmental degradation and rapid climate change.

Wreathed in smoke to drive away defensive clouds of giant bees, 26-year-old Som Ram Gurung dangles dangerously 100 metres (325 feet) off the ground, slicing off dark and dripping hunks of delicious honeycomb.