The original "Planet of the Apes" remains one of the best sci-fi movies of all time. This is a movie with incredible makeup effects that hold up to this day, an air-tight script with poignant social commentary co-written by "The Twilight Zone" creator Rod Serling, and a stellar performance by Roddy McDowall.

Of course, the film is arguably best remembered for having one of the greatest and most memorable twist endings in all of cinema, which Tim Burton utterly failed to replicate. The ending of "Planet of the Apes" has been referenced and parodied to death for decades — though, if you somehow have remained unsullied until now, we will not ruin it. It is also an ending that is rather hard to top, though that didn't stop Twentieth Century Fox from trying.

One thing that makes the "Planet of the Apes" franchise so unique is that it is an extremely rare case of a franchise getting bigger, and more inventive even as its budgets kept decreasing — even though contemporary critical reception wasn't all that. It is hard to imagine nowadays a hugely popular and acclaimed movie getting cheaper with each sequel, while still offering increasingly more imaginative scenarios, but that's Hollywood for you. At the time, sequels were seen as failures, and even if they still made money, the budgets decreased since it wasn't expected that the sequels would outperform the original — a sign of the many changes Hollywood has gone through in recent decades.

This started with "Beneath the Planet of the Apes," the first sequel, which offered a distinct blend of B-movie cheese with some poignant political imagery, as well as a bold ending that nearly put a nail in the series' coffin.

Let's Do This One More Time

After the massive success of the first "Planet of the Apes" movie, searching for a sequel script wasn't easy. Several different scripts were considered and ultimately discarded, including one by returning writer Rod Serling and even original author Pierre Boulle, who wrote a script about a human revolution that ended with apes reverting to their primitive origins.

The final film is written by "Goldfinger" scribe Paul Dehn and directed by prolific TV director Ted Post. The thing about "Beneath the Planet of the Apes" is that, for its first 50 minutes or so, it is essentially a "Planet of the Apes" remake. We follow a human astronaut who stumbles upon the ape city and gets captured and tortured for a bit. He proves he is smart and escapes, venturing outside the city to the forbidden zone. The big difference is that this time we follow James Franciscus as Brent, who is essentially discount Charlton Heston — Heston famously refused to return for the sequel until he was guaranteed his character would only appear in the beginning then die immediately.

Still, the film has some good stuff, like political allegory and bizarre anti-war imagery — shots of chimpanzees protesting the gorilla-led war against humans with signs that heavily resemble the anti-Vietnam-war posters seen at the time of the film's release. The scene is even shot handheld to resemble a TV news report.

This is a B-movie unafraid to be both cheesy and dark, bold and unhinged. While repeating the scene of the astronaut realizing they're on what they think it's an alien planet, the captain of Brent's ship laments the death of everyone he knew in a rather somber scene. On the other hand, we have a group of mutants worshipping a phallic missile.

But that's nothing compared to the ending.

The Beginning And The End

During production, the then-president of the studio, Richard D. Zanuck, was fired by his own father, then-chairman. Perhaps in retaliation, perhaps not believing the sequel would be successful, perhaps because he wouldn't be involved in any future sequels, Zanuck had the idea to end the franchise once and for all. He took Heston's suggestion for an ending, which had Taylor return for a scene at the end of the film, die, and accidentally destroy the planet.

That's right. In the last eight minutes of "Beneath the Planet of the Ape," the love interest is killed, the human mutants mostly commit suicide, the new protagonist is shot by a firing squad, and the leader of the gorilla army is shot in the back. As for Heston's Taylor, with his last breath after being mortally shot, he activates the doomsday bomb and blows up planet Earth. The film ends with the screen fading to white, and a narrator confirming the bleak ending, saying:

"In one of the countless billions of galaxies in the universe lies a medium-sized star. And one of its satellites, a green and insignificant planet, is now dead."

Of course, by the time this ending was shot, the sequel was already being planned. But even before the franchise gave us the dark and politically charged ending of "Conquest of the Planet of the Apes," there was the death of the entire planet. For a studio to so clearly destroy a franchise, with seemingly no way for a sequel, is unimaginable today, but that's what makes "Beneath the Planet of the Apes" so special.

Read this next: 12 Underrated Sci-Fi Shows That You Need To See

The post Charlton Heston's Beneath The Planet Of The Apes Ending Would Have Put A Nail In The Series' Coffin appeared first on /Film.