Dark Depths

The Dark Depths is just beyond The Great Maw in Hollow Bastion. Several cutscenes are shown at the Dark Depths such as Axel confronting Sora and tells him of the Organization XIII's plans with Kingdom Hearts when Saïx appears in to try and capture Axel. Once the Master Control Program has been defeated and the place has been renamed back to Radiant Garden, Sora can find and battle Sephiroth here. You can see the Villain's Vale where Maleficent used to reside from the Dark Depths. In Kingdom Hearts, the area where you fight your first Behemoth and seal Hollow Bastion's Keyhole is also called Dark Depths, despite no similarities or connections.