I never quite knew what mondo was supposed to mean — vaguely “over the top” was my understanding — and I certainly didn’t know that it had a clear, specific origin:
The fad started with the Italian film Mondo Cane (A Dog’s World, also a mild Italian curse; “mondo” literally means “world”) made in 1962 by Gualtiero Jacopetti and proved quite popular. Mondo films are often easily recognized by name, as even English language mondo films often included the term “mondo” in their titles. Over the years the film makers wanted to top each other in shock value in order to draw in audiences. Cruelty to animals, accidents, tribal initiation rites and surgeries are a common feature of a typical mondo. Much of the action is also staged, even though the film makers may claim their goal to document only “the reality”.
Although the craze really hit in the 1960s, it made a comeback with Faces of Death in the 1980s.