A group of tourists riding camels on a dirt path accompanied by pedestrians.
Humans riding.
Nobody is riding
A young boy is on the monkey bars
including what is left of ours.
Two buses stop for passengers at a bus stop.
We discuss the major sources of each of these three categories in the remainder of this section; monetary valuation of these benefits, avoided health effects, and avoided ecological effects.
There is a person high up in the air
Two children ride their sleds.