In China's Mu Us Desert, Inner Mongolia Autonomous Region, a reunion 26 years in the making moved Yin Yuzhen to improvise a song about the land she has spent decades greening.

She was reunited with American teacher Ronald Sakolsky, who raised $5,000 to support her tree-planting work in 1999. The two recently reconnected after Yin's online appeal to find him went viral.

She sang of poplars and willows planted across thousands of hectares to block the wind, hold back the sand and bring the soil back to life.