Beneath the Planet of the Apes (1970)

Astronaut Brent crash-lands on a distant planet in 3955 A.D. while searching for his predecessor, Taylor. He discovers a world ruled by intelligent apes and joins forces with the mute Nova, who wears Taylor's dog tags. In Ape City, Brent witnesses the militaristic gorilla General Ursus planning an invasion of the Forbidden Zone. After escaping captivity with the help of the chimpanzees Cornelius and Zira, Brent uncovers a hidden society of telepathic humans who worship a powerful nuclear bomb.