The Mysterious Cities of Gold
I wasn't able to watch it as a kid because it aired outside my viewing hours, but it stuck in my brain as I'd rarely catch a glimpse of it being advertised. My child brain would sometimes mix it up with another anime from then I don't know the name of because it seemed only to ever air on Telemundo. That one had like a red 'n blue robot in it.
Aaanyway, I eventually rediscovered it and got the whole series through...means.
It's kinda shocking how much Avatar: The Last Airbender is in this show...or vice versa I suppose. It's a big journey anime that spends damn near the entirety of its something like 20+ episodes getting to the titular Cities of Gold and its shockingly dedicated to telling a serialized story at a time when there was no reason to and every reason not to. And it looks incredible! It's old school anime, so the animation's got rough patches, but the actual visual style and art direction puts it miles ahead of it contemporaries.