Beasts Castle

Sora and his party arrive in, appropriately enough, the castle's Entrance Hall. They cannot go out the castle's main doors yet, but a small door to the east leads to the Parlor, where they have an abrupt encounter with Beast and some Heartless. The Parlor also holds the world's Moogle shop, as well as a save point. To the north back in the Entrance Hall is a grand staircase that leads to both wings of the castle; going straight ahead takes the party into the magnificent Ballroom, where a number of plot points take place.
Going to the east takes the party to the East Wing, where Belle's Room is. Here, she provides information, a few chests, and a save point. Going to the west takes the party to the much larger and more involved West Hall. Suits of armor block the stairs to the right, and so the only place Sora and his group can explore, once The Wardrobe is moved, is the Undercroft. After a boss battle, the party reaches the Dungeon, where they meet Beast's servants and learn of the world's events. The group goes out of a secret passage in the Undercroft to the Secret Passage, which allows them to sneak behind the armored suits blocking the stairs back in the West Hall. Entering the door opposite the Secret Passage takes the group to the West Wing proper, at the end of which is Beast's Room.
During the second trip to Beast's Castle, the main doors of the Entrance Hall unlock, allowing Sora to access two more areas, the Courtyard, full of fighting gargoyles, and the Bridge, where the final confrontation with Xaldin takes place.