Requiring the British Royal Family to promise not to reveal the ending as a condition for viewing has to place a movie on the "top twenty."
Further, simply a better movie than most in the listed twenty. (And even has a patent sub-theme for character Leonard Vole (Tyrone Power)). Shame on premiere.com.
From IMBD: Helm (Dietrich) claims correctly that she had never testified that what she had written in the letters was the truth, merely that she had written them. Christie exploits this assumption by the jury brilliantly and credibly, and is a diabolically clever plot twist.
Laughton, Dietrich, Lanchester
Of the inclusion of "Planet of the Apes" in twists, recall an episode of the Twilight Zone ("I Shot an Arrow Into the Air", originally aired 15 Jan 1960 )with the same theme. Wikipedia writes:
A manned space flight crash lands on what the astronauts believe to be an unknown asteroid. Their expectations of survival or rescue are bleak. Only four of the crew survive, one of whom is barely alive. After he dies, the three remaining men, Corey, Donlin, and Pierson decide to trek out into the barren desert to see if there is anything — shelter, water — that might improve their chances of survival. When Corey and Donlin reconvene, it seems that Pierson is dead and Corey filched the water supply from his dead body. Donlin, the commanding officer, forces Corey at gunpoint to lead him to Pierson's body. They find Pierson, still barely alive, who with his last bit of strength draws a primitive diagram in the sand with his finger. Corey then kills Donlin and sets out alone, confident that he will survive longer now that he has all of the water supply. After wandering aimlessly for an extended period, he sees a set of power lines and realizes that that's what Pierson was attempting to draw. A highway and road signs reveal that the ship crashed on Earth and the men had been in the Nevada desert the entire time.
As a blog noted:
The one where the astronauts land on a desert planet. 1 of the astronauts goes to look around. he comes back and dies but not before he draws something in the sand. its a vertical line with two horizontal lines in it. the other astronaut thinks its part of the alien language at the planet they're on. so he starts wandering around looking for a sigh of civilization. he starts getting more and more tired until he reaches the top of a huge sand hill. he looks over the hill and.....dies. then they show us what was over the hill. it was Las Vegas. What the other astronaut had drawn in the sand was a telephone pole.
The episode was written by Rod Serling (story by Madelon Champion). Serling did the script for Planet of the Apes. Should recycling get one into the "top twenty"?