In many mountainous parts you can fly from one artificial lake to the next, see them all lined up along a river. There are a lot of hydro electric dams around the world.
What also surprised me from nature is how much large rivers move around. The Volga in Russia looks like it moves every spring. So many different water courses, cut off parts, huge landmass that gets flooded every spring. Lots of pretty flow patterns to see from the air.
The same in the deserts, all the flow patterns from seasonal rain are awesome to see from the sky. And you can really see how water brings life, a bloom of green spreading out where the rivers flow out over open desert. Desert rivers are trees of life as seen from the sky.