The Forbidden Land, Eureka is an optional dungeon in the game Final Fantasy III which contains some of the best equipment in the game. A gateway to it can be found at the bottom floor of the Crystal Tower, but the Eureka Key is required. Doga and Unei unlock the Eureka Key, and give it to the Warriors of the Light, granting them access to Eureka, knowing they need better equipment to fight Xande. This equipment was sealed away long ago because considered too powerful for humans to behold.