I'm trying to figure out what anime I'm thinking about. I remember watching it when I was a kid.

It's basically about this girl in a desert world. It involves these weird looking creatures. I don't really remember what they look like anymore. I remember windmills and weird looking flying machines.

A specific scene I remember is her and this one guy fell down through some quick sand or something into this cavern below.

Anyway, does anyone know which one I'm talking about?

Nausicaa of the valley of the wind. II was looking for this one too, at on point.