Planet of the Apes (1968).It has the look and feel that John Carter should have had.
Exchange the apes for the green men of Mars, and there you go.Beneath The Planet of the Apes is similar to Book 2: Gods of Mars.
Planet of the Apes is extremely similar to Burroughs "At the Earth's Core"
Yes, ... Planet of the Apes is a mashup of "A Princess of Mars" and "At the Earth's Core".
Planet of the Apes was a poor adaptation of the original French book.