Kingdom Hearts/Traverse Town

Traverse Town is the most important world in the game. It's where the item and accessory shops are located, and also the Gummi Ship's location. Here, you meet Donald and Goofy, who end up helping you throughout the duration of the game and becoming main party members. Traverse Town is split into three districts, the first district being the only safe one at the moment, the others inhabited by endless swarms of Heartless.

First District
A cutscene is shown featuring Donald, Goofy, and Mickey Mouse's dog, Pluto. They're on a quest to find the wielder of the Keyblade, and are seeking the help of Squall Leonhart, here known as Leon. Donald leads the way and Goofy obediently follows, but Pluto sneaks into the alleyway where an unconscious Sora is located. Eventually, Sora wakes up, mistaking the scene for a dream only to discover that it's not a dream, and that he's in a different world. From the alleyway where you start, take a turn and head down the path to see the entrance to District 1 and Traverse Town altogether. From the stairs, turn around and walk into the building. This is Cid's accessory shop. After Cid and Sora have a conversation, you'll be free to explore the area. There is a also a Save Point in the shop. Next to Cid is a wall cabinet with a treasure chest sitting on top. After getting out of the shop, go down the stairs, turn right and then back for a treasure chest.

Postcard Side-quest
To the left of the accessory shop is the item shop, run by Donald's three nephews, Huey Louie and Dewey. Go out the back door to be taken to another alleyway. Right to the left of the main staircase is a mailbox. If you give it 10 post cards, you'll get a prize. The first post card can be found right inside the item shop. From the counter, lock-on to the ceiling fan with psx: R1. Jump from the counter and hit it with your keyblade for the first post card. Go back to the mail box to give it the post card. The second post card will be outside Cid's shop. Jump onto the barrels and onto the roof of the nearest building. Jump to the other side of the same roof. Walk around the other side to open a treasure chest containing he second postcard. After sending both postcards, you will receive a Mythril Shard.

Onto the Second District
Behind Cid's accessory shop will be the doors to the second district. Walk into them for a cutscene.