I first read the "John Carter of Mars" series in high school, and recently re-read several of the books. The series is irregular in quality, but highly imaginative with magnificent literary visuals.
So I could never quite figure out why the books hadn't been turned into movies. I guess either the Burroughs estate forbade it, or the caliber of special effects just weren't up to the challenge. And maybe the suggestion that the Barsoomians went around nearly naked might have put off a lot of people.
As I recall, there was a borderline-softcore-porn adaptation of "A Princess of Mars" put out a few years ago, which The Husband said was only watchable in fast-forward.
So now I'm pretty enthusiastic about the new "John Carter" film that's coming out. The review I read this morning was poorly constructed, but the writer seemed to genuinely like the movie. This is the very sort of story CGI was created to serve, because Burroughs put in so many fantastical elements that actors on wires or in rubber suits just couldn't pull off convincingly.
I'm hoping to con The Husband into going to see this one on the Big Screen. Science fiction epics just lose something when viewed on a TV set.