Cavern of Remembrance

The Cavern of Remembrance (追憶の洞 Tsuioku no Hora) is an area of the world Radiant Garden that was added-on in Kingdom Hearts II: Final Mix+. It is requested that the player be at a high level, as the enemies within are extremely powerful (rivaled only by the enemies in the Hades Paradox Cup). The cave leads to a courtyard known as the Garden of Assemblage, which has 13 portals that contain data replicas of the members of Organization XIII.

The entrance, Cavern of Remembrance: Depths, holds a balloon in the left section, which drops Drive Orbs and also allow you to obtain items. By continuing to go deeper down inside you will eventually lead to a hall with a lot of powerful Heartless. However this can be avoided by several pathways in the room.

The rooms past the Depths include the Mining Area, in which Sora must ride whirlwinds and jump and glide to get past the machinery, and the Engine Chamber, in which Sora can get damaged by steam and Heartless, such as the Perplex, the Air Champion, the Reckless, the Bark Hound, the Air Viking, the Rune Master, flying around while being impeded by conveyor belts. Each room is separated by a section of a large area called the Mineshaft, in which Sora must use his abilities learned from his forms (mainly Glide and Air Dodge) to get past the obstacles. Following each obstacle is then followed by a scripted Heartless battle.

The second to last area, Transport to Remembrance, is a white hall with multiple Nobody battles.

After that is the Garden of Assemblage, in which the data replicas are stored. Sora must activate a computer to access the data battles. Note that the computer can be accessed any time, it's just that if there are some battles that Sora hasn't completed yet (such as Xigbar or Vexen), the data battles cannot be accessed.

Through the back of the Garden of Assemblage, Sora can get to the Restoration Site, in Radiant Garden, creating a link to that area. That way, Sora doesn't have to go through all of Cavern of Remembrance to get to the Data Battles.

Trivia

 * Transport to Remembrance bears an uncanny resemblance to the hallways of Castle Oblivion.
 * The Heartless that live in the Cavern are power-boosted and recolored versions of their normal counterparts, such as Air Pirate and Air Viking, the Devastator and the Reckless, or the Rabid Dog and the Bark Hound.
 * The balloons filled with Drive Orbs at certain points of the Cavern of Remembrance indicate the Drive Form that Sora must use to get past that area. Sora needs to use High Jump (acquired from Valor Form) to get over the wall at the entrance (hence the red coloration). At the entrance of the Mineshaft, Sora needs to use Quick Run (acquired from Wisdom Form), hence the blue coloration of the balloons, and so forth. It should also be noted that whenever Sora enters into the corresponding Drive Form, the balloons light up.