<photo: children in Phortse, Nepal>
前人栽树，后人乘凉 is a Chinese idiom which literally translated means "one generation plants the trees under whose shade the next generation rests".
a close Western equivalent of this idiom would be "pay it forward" which means that "if something good happens to a person, he turns around and does good for someone else. The idea here is that instead of paying back to the person who has helped you, the good deed is passed forward to someone else."
both idioms illustrates the importance of doing good, whether it's planting trees, paying it forward or building base camps to help children reach their peaks (not literally). each of us can make a difference, and perhaps find our purpose at the same time.