Eureka is an optional dungeon, but it has all of the most powerful equipment in the game. It's entrance is in the Crystal Tower.

From the entrance of Crystal Tower, go straight into the center room.

Chests (19):

• Fuma Garb
• Chocobo's Wrath (x2)
• White Musk (x3)
• Elixir (x4)
• Phoenix Down (x3)
• Ribbon
• Shuriken (x4)
• Omnirod

Items (5):

• Moonring Blade (boss: Amon)
• Masamune (boss: Kunoichi)
• Excalibur (boss: General)
• Elder Staff (boss: Scylla)
• Ragnarok (boss: Guardian)