This is one of the last matriarchal societies on earth, where the women hold power. They make the major decisions, control household finances, have rightful ownership of land and property and full rights to the children born to them. Most notably, the Mosuo practice something called 'walking marriage' where, from the age of 13, women can choose to take lovers - as many or as few as they wish - from men within the tribe. Choo Waihong discovered the Mosuo several years ago and lived with them for six years, becoming part of a Mosuo family and of the wider community - the only non-Mosuo to have ever done so. The story of her time in the remote mountains of China is both poignant and compelling: a vibrant glimpse into a way of life that teeters on the knife-edge of extinction.