Jungle Opera

This is a speculative tale that takes place in undiscovered or semidiscovered country in the present or "recent" (usually no earlier than the early 20th century) past supposedly on this Earth. As opposed to say a High Fantasy in a Medieval setting, or a Space Opera in a far future-like setting. As the title indicates it often takes place in a tropical rain forest though that is not necessary. The key point is that Willing Suspension of Disbelief is provided primarily by the use of settings that are regarded as exotic, mysterious, dangerous and above all, far away by most readers, yet still on this world; rather then providing a whole imaginary world "in a galaxy far away". A typical setting for instance, might be The Amazon, Darkest Africa, or Shangri La. There are occasional similarities with the Space Opera, the two genres can each borrow tropes normally associated with each other and there is potential for crossovers (aliens can for instance kidnap the intrepid explorers, or perhaps a Space Opera can have a story take place on a jungle planet). However some elements of a Jungle Opera can be less flexible then other speculative sub-genres by the nature of operating in "closer proximity" (so to speak) to Real Life.

Jungle Operas tend to feature Precursors, Lost Colonies, Ancient Artifacts, and the like; ruins-filled-with-deathtraps is one of The Oldest Ones in the Book. This will also likely involve Ancient Astronauts and have an Adventurer Archaeologist as one or more of the characters. Oddly enough the experiences of Real Life explorers did sometimes have a suspicious resemblance to this genre. We don't think that any secrets man was not meant to know have been discovered -- not that anyone would admit it if there have been some. Maybe the world was not yet ready?

Often involves a Lost World. In some versions the story is about a quest to find this, and a Lost World is a MacGuffin Location.

Comic Books

 * Tintin had this every once in a while (first one in Africa, then in India, then in Peru, etc.) but one of his later books set in Southeast Asia has this with a twist:.
 * Many a Scrooge McDuck story.

Film

 * Indiana Jones is the example everyone remembers.
 * The Librarian is a satirical version.
 * Parts of the film Gunga Din, what with the lost temple and all.
 * The Mummy Trilogy
 * Secret of the Incas, which was a major inspiration for the adventures of Dr. Jones.

Literature

 * King Solomons Mines by H. Rider Haggard is the Ur Example.
 * Sir Arthur Conan Doyle's The Lost World probably counts. The heroes end up on a lost plateau in the South American jungle with dinosaurs, ape-men, diamonds and Everything Trying to Kill You.
 * Tarzan
 * The Jack West series by Matthew Reilly.
 * The Serpent, the first novel in Jane Gaskell's Atlan series, takes place in a prehistoric civilization in ancient South America and contains such elements as giant carnivorous birds and a reptile-man villain. The rest of the saga is more in the vein of a Lost World.
 * Doc Savage

Live Action TV

 * Tales of the Gold Monkey.
 * Bring Em Back Alive
 * Lost is primarily this genre, with the Island being an archetypical Lost World.
 * Relic Hunter

Newspaper Comics

 * Jungle Jim

Tabletop Games

 * GURPS volume Cliffhangers has a lot about this kind of story and how to draw a typical plot of this kind.

Video Games

 * Uncharted, particularly the second game.
 * Tomb Raider.

Western Animation

 * The Road to El Dorado
 * DuckTales did this sometimes.
 * So does Tale Spin.
 * The "Just For Fun" series of Books Within A Show in the My Little Pony Friendship Is Magic episode "Read it and Weep", which is heavily based on Indiana Jones.