The Whirlwind Maze is an area of the game that you travel through while chasing down Sephiroth. It is located just over Gaea’s Cliff and eventually leads to the Northern Cave.
The story of the game takes you through the Whirlwind Maze after you travel through the Icicle Village, then the Great Glacier, and finally Gaea’s Cliff. Check out the Whirlwind Maze walkthrough page for details.
There is no way to revisit the Whirlwind Maze so it is important that you pick up all of the items in this area as you pass them. Some of the items include:
Neo Bahamut Materia
Kaiser Knuckle
MP Turbo Materia
Poison Ring
The map below shows the location of the Whirlwind Maze, which is close to the Northern Cave, but remember that you can’t reach this area after you have already passed through it: