An astronaut crew who crash-lands on a strange planet in the distant future. Although the planet appears desolate at first, the surviving crew members stumble upon a society in which apes have evolved into creatures with human- like intelligence and speech. The apes have assumed the role of the dominant species and humans are mute creatures wearing animal skins.

References:
https://en.wikipedia.org/wiki/Planet_of_the_Apes_(1968_film)