have you seen a BBC produced show called Planet Earth.
they've been showing it nightly over here on UKTV history (or whatever its called) anyways, it makes me happy to pay the annual license fee; farking amazing!
they covered rivers the other day, inclusive of the Colorado but last night it was all about the caves.... some of those in mexico are hardcore cruster!!
Just coz you don't understand it
Doesn't mean it makes no sense!