Can a planet long endure half-human and half-ape? What with a war overseas and civil unrest at home, that was probably the least of America's problems when this sequel debuted in 1970. As far as sequels went, it wasn't terrible but it definitely didn't approach Godfather 2 status.

Heston's back along with Linda Harrison, Maurice Evans and Kim Hunter. The script features newcomer James Franciscus as astronaut, John Christopher Brent, sent out on a rescue mission after Taylor's ship was found to have gone off course. But this one gets weird fairly fast as one side of the Forbidden Zone is populated by mutants and you get to them by walking through the ruins of the New York subway system.

As a longtime strap hanger, I can attest to witnessing more than a few mutants riding the rails with me, so this depiction was not too much of a stretch. But there were no happy endings in this picture. Taylor and his mate Nova both die when the gorilla troops invade the underground lair of the mutants. But they don't get to enjoy their conquest as an atomic bomb gets detonated and everything gets blown to pieces.

Some bright studio bulb figured our appetite for all-things ape was unlimited. So it was that "Escape from the Planet of the Apes" came out in 1971. Heston must have had a premonition as he only appeared in a couple of flashback scenes. The biggest newcomer in the film was Sal Mineo, who, along with Roddy McDowall, Kim Hunter, had somehow managed to survive the atomic blast from "Beneath the Planet of the Apes. They then repair Taylor's spaceship and without any flight training at all pilot the craft back to Earth, circa 1973. Who woulda thought they were all so handy?

The plot puts the apes before a presidential commission before they wind up getting shot at the end of a convoluted sequence. The film ends showing their orphaned baby speaking the words, "Mama? Mama?" (At the time, I was thinking the same, dreading the prospect of yet another sequel.)

Another year, another ape movie. "Conquest of the Planet of the Apes" hits the theaters in 1972. The plot reminded me loosely of Karel Capek's early 20th century play R.U.R., which recounts the tale of a robot rebellion against humans. In "Conquest," humans take apes, first as pets and then to serve as domestic slaves. Of course, that leads to the inevitable ape revolt.

It's 1973 and "Battle for the Planet of the Apes" wants to settle the burning question once and for all: Who had the right to rule Earth, ape or man? To help answer that question, the studios enlisted the services of the great John Huston to play the role of the "Great Lawgiver" in this sequel. Apes and mutants are again at each other's throats but at the end, apes and humans decide opt for mutual coexistence. Kumbaya.

"Rise of the Planet of the Apes" hits the theaters on Aug. 5. Hard to know what to expect but the various teaser clips have definitely piqued my interest.