Merlin's House

There are two "Merlin's House"s: one in Kingdom Hearts and one in Kingdom Hearts II. They each have different purposes in relation to the game in which they appear.

Kingdom Hearts
Merlin's House is a location situated in Traverse Town and can be accessed in one of two ways, via the Second or the Third District. If going via the Third District, which is the first way made available to the player, one must find the door with a flame emblem on it. Upon finding it, the player can only unlock the door by casting fire on the Fire Emblem. After entering the door, the player needs to jump over moving rocks flowing in the river to reach Merlin's House. The house itself is divided into three sections.
 * The Magician's Study is the "ground floor" of the house. This is where the player can speak with Merlin and the Fairy Godmother, or enter the 100 Acre Wood via the book on Merlin's table.
 * The Magician's Lab, located in the attic (accessible by talking to Merlin) is a magic training ground. While practicing magic, MP becomes infinite (it restores when the last MP bar is spent), and the player can use as many spells or summons as desired against Merlin's flying furniture, without losing any MP. In fact, after practicing magic, MP is always fully restored, regardless of how much or how little the player had when starting.
 * The Secret Waterway, referred to by Merlin as "the cavern", is underground. It connects to the Alleyway, which in turn connects to the Second District. However, this connection is not accessible until the player obtains the Red Trinity.

Kingdom Hearts II
The Merlin's House in this game is found in the reconquered Hollow Bastion. It can found by going through the Marketplace and entering the Borough. There stands Merlin's House which is, in this version, home not only to Merlin, but to the Hollow Bastion Restoration Committee. It has all the same inside features as the Kingdom Hearts version, with the exception of the Fairy Godmother, and the addition of a large computer, which one can always find Cid working at. The player can also access the 100 Acre Wood world from here.