It's used all the time in documentaries, often over pieces of time lapse footage. It's got a kind of neo-classical vibe, but it's probably donkey's years old - maybe a bit Eno-ish?

Basically, there's a kind of three-note bit on strings (or string-like synths) that goes DOOOOOOOO, DOOOOOOOOOOOOOO( higher pitched), DOOOOOOOOOOOOOOOOOOOO (lower pitched). Then over the top there's a twinkly descending piano arpeggio, all lovely like a falling waterfall. It's really recognisable.

If someone finds it, it will probably turn out to be nothing like this description.