Krematoa

Krematoa (also known as the Lost World) is a large, hidden area in the game Donkey Kong Country 3: Dixie Kong's Double Trouble! Krematoa's name is a pun of the volcanic island Krakatoa. Boomer is the Brother Bear of Krematoa and resides in a bomb shelter near the world entrance. In the original Super Nintendo version, the world's theme is "Krematoa Koncerto", which is a more sinister arrangement of the game's main map theme, "Northern Kremisphere". Krematoa is the only world to not have a Swanky's Sideshow or a secret cave.

Krematoa takes place in a dormant volcano, and much of its terrain consists of cliffs and caverns. Contrarily, Krematoa also has both a jungle and a forest area, located at opposite ends of Krematoa. A large lake is in the center of the area.

Krematoa is somewhat similar to the Lost World from Donkey Kong Country 2: Diddy's Kong Quest. Both worlds require the Kongs to pay an exclusive currency (Kremkoins or Bonus Coins) to access each of the levels, and both worlds have a lake in the center where the final boss battle takes place.

History
Krematoa was originally just a legend believed to exist by Blunder. As the Kongs progress through the game, Blunder slowly leaks clues as to how they can find Krematoa. He reveals the actual method when the player completes the game. Krematoa once stood to the east of Mekanos but at some point had sunk to the bottom of a lake. The only remains of Krematoa are four rocks, each pointing in a compass direction. With the Hover Craft or Turbo Ski, Dixie and Kiddy must circle around these rocks in a clockwise direction to make Krematoa rise out from the water.

Inside Krematoa, there is a group of large boulders, each one blocking the path to one of the levels. The Kongs must visit Boomer's Bomb Shelter and pay him Bonus Coins so that he sends explosives to destroy a set of boulders in the path. The Kongs can then access that level. The Kongs are rewarded a cog for completing a level. Boomer puts the cogs on a machine in his bomb shelter.

When all five cogs are on Boomer's machine, a tremor occurs in Krematoa, causing Baron K. Roolenstein's Knautilus to rise up in the central lake. The lake turns from blue to red, and the entire Krematoa glows a faint red, which also affects each of Krematoa's levels (although not in the Game Boy Advance remake). After the Knautilus rises, a bridge rises out of the lake and extends to the submarine. In the Game Boy Advance remake, the Kongs can swim across the water to reach the Knautilus.