This subgenre begun with Paolo Cavara's, Gualtiero Jacopetti's, and Franco Prosperi's Mondo Cane, from which the subgenre takes it name and of which subsequent films utilized the word to identify themselves as of being in the subgenre. With the English translation of the film's title being A Dog's World, the film was predominantly an exploration of unusual cultural practices in Africa and Asia, such as a cannibal tribe in Africa with ritualistic boar clubbing and a practicing South Pacific cargo cult. Europe and America had their share of weird behaviour represented, too, such as inbred Italians and a restaurant in New York where posh patrons dine on insects. For a time subsequent Mondo films would adhere to this premise. In the 80s the films dropped unusual cultural practices as subject-matter and begun to focus exclusively on gruesome ways in which people and animals can die, with such films sometimes regarded as being in a sub-subgenre called "Death Films". Another offshoot common in The '60s was to documentaries about strippers and other excuses for women to be topless.
More often than not, the legitimacy of these films as documentaries was limited. Rarely did the filmmakers do the research; content was exaggerated and sensationalized in hopes of fulfilling the films' primary purposes of drawing as large a box office return as possible. Though the films would boast of featuring authentic footage, the greater majority of what was in them was in fact staged. The aforementioned death films loved to boast of featuring authentic killings; but it is common knowledge that never, in the history of cinema, has an actual human being been deliberately killed for purposes of film. The animal killings, on the other hand...
Sensationalist documentaries existed (thought not in a proper "mondo" format) before Mondo Cane. In fact, one of Thomas Edison's early films was the electrocution of an elephant, making this trope Older Than Television.
Anyways, aside from the aforementioned Mondo Cane, here are some titles belonging to the Mondo subgenre, with English translations in brackets where appropriate:
- Il Mondo di Notte (The World by Night) Gualtiero Jaccotpetti's documentary about nightclubs made before Mondo Cane. Quite possibly the Ur-Example.
- Addio zio Tom (Goodbye Uncle Tom) About the slave trade.
- Africa Addio (Goodbye Africa) About European colonial powers leaving Africa in a state of chaos. Noteworthy for having the only combat footage taken of the Congo Mercenaries.
- Faces of Death
- Faces Of Gore
- La Donna nel Mondo (Women of the World) About the role of women in various countries.
- Mondo Cane 2 (A Dog's World 2) Also edited and released as Mondo Pazzo (Insane World)
- Mondo Cane 2000: L'incredibile (A Dog's World 2000: The Incredible) Not an official sequel.
- Mondo Cane Oggi (A Dog's World Today) Not an official sequel.
- Shocking Asia
- Svezia, inferno e paradiso (Sweden: Heaven and Hell), a largely sensationalized, titillating examination of liberal sexual attitudes in Sweden. Now best known for its soundtrack, from which "Mah Na Mah Na" originated.
- Traces Of Death
- Ultime Grida Dalla Savana (Savage Man Savage Beast)
- Mr. Mike's Mondo Video, a parody from Saturday Night Live head writer in The '70s, Michael O'Donoghue.
- When Animals Attack! is a live-action TV version of this. The FOX network was (in)famous for running these specials in The '90s.
- ''The S From Hell'' is a more modern (made in 2010) and more low-budget version of the genre. Unlike others it goes about the Screen Gems logo and the horrible effects it has on society.
A decent list (with mini-reviews) can be found here.