A rare optic sight, the "Brocken spectre," which occurs when a person stands at a higher altitude in the mountains and sees his shadow cast on a cloud at a lower altitude.
There is a tribe in India that has learned to make living bridges out of Ficus tree roots. The bridges take 15-30 years to complete.
They stretch from 15 to 250 feet over deep rivers and gorges, and can bear impressive loads.