The Lost World is the name of a mysterious jungle-like land hidden within the Crocodile Isle one of the many known locations in the Donkey Kong universe. It first appeared in Donkey Kong Country 2: Diddy's Kong Quest and Donkey Kong Land II. It is the secret kingdom of the Kremling Krew lorded over by King K. Rool. It is also the birthplace of the Kremling species.
The Lost World itself is located deep within the Crocodile Isle and is fairly large in size. The land also has a bizarre climate, some portions of it being a jungle-like environment, others being volcanic mountains and some frozen caverns. In the center of the lake at the heart of the Lost World is a temple-like structure built into an volcano known as the Krocodile Kore, which happens to resemble a Kremling's head. The volcano is home to the energy generator which pumps out an upward stream of purple, white and blue-colored supernatural energy which somehow powers the entire island itself.
The centerpiece inside the volcano is a temple-like palace, which has an altar, a large amount of treasure and bones, and armored Kremling statues in the background of it.
While travelling through the volcanic arena called the Crocodile Cauldron, Diddy and Dixie Kong encountered a large burly Kremling named Klubba. Klubba had been ordered by Kaptain K. Rool to guard the many entrances of the Lost World and to not let anyone pass. However, Klubba would let the 2 young kongs for the price of 15 Kremkoins per entrance. In order to unlock all 5 of the Lost World's entrances, the Kongs would have to collect all 75 Kremkoins scattered about the game's levels. If the Kongs manage to obtain the game's seventy-five Kremkoins and clear all the levels in the Lost World, then the mouth of the Krocodile Kore will open and the Kongs will be free to venture inside.
Here in the Krocodile Kore that Diddy and Dixie Kong faced the mad K. Rool and, after a long fight (which consists mostly of dodging blasts from K. Rool's blunderbuss), the Kongs managed to defeat the Kremling king who was then flung into the energy flow of Krocodile Kore. K. Rool's bulk ended up blocking the volcano's flow of energy, which subsequently built up. Eventually, the Krocodile Kore exploded and collapsed due to excess energy build up; this explosion ended blowing off the top of the island and sinking the rest of it.
In Donkey Kong Land 2, the Lost World is risen up from the bottom of the ocean along with the rest of the Crocodile Isle. This time there is only one entrance to the Lost World, it is located near Gloomy Gulch. This time around, Diddy and Dixie Kong needed to pay Klubba all 47 Kremkoins at once to enter the Lost World. After paying Klubba and entering and clearing all of the Lost World's levels, the Kongs get the chance to once again enter the Krocodile Kore (which no longer pumps out energy). Once again K. Rool is defeated and the whole Crocodile Island collapses and sinks to the bottom of the sea, this time permanently.
- The German Donkey Kong comic "Bumm-Badabumm im Urwald" featured a place called the "Lost Land". Despite being located on the Donkey Kong Island, the Lost Land was seemingly the Bumm-Badabumm im Urwald version of the Lost World, as it is filled with ancient Kremling ruins and it is where the Kongs have their battle against Kaptain K. Rool.
- The manual for Donkey Kong Country 2: Diddy's Kong Quest states that the Lost World may be the place of origin to the Kremlings.
- Another secret area called the "Lost World" was featured in Donkey Kong Land III. All of the DK Coins must be collected in order to enter a battle with a Baron K. Roolenstein. Baron K. Roolenstein himself will attack by throwing bombs and firing laser beams.
- In Donkey Kong Land III, a contest had taken place in which several contestants had to find the Lost World.
- The name itself is also a reference to the 1960 film The Lost World.