The Destiny Islands is a world created for the Kingdom Hearts series. This is where the three main protagonists, Sora, Riku and Kairi live a peaceful life. Kairi arrived to these Islands a night, her memories lost. Selphie, Tidus and Wakka from the Final Fantasy series can be seen here as inhabitants of these Islands. This is where the adventure begins after Sora, Riku and Kairi get separated due to the Heartless' attack. The basic controls and fighting practice takes place in here.
Traverse Town is an original world created for the Kingdom Hearts universe. Sora arrives in Traverse Town after the attack on the Destiny Islands and is awakened by Pluto. He finds himself alone and without knowledge of his whereabouts until he meets Leon, Yuffie, Aerith and Cid from the Final Fantasy series. It is in here where he learns about his connection to the Keyblade and meets Donald and Goofy, to then embark on his journey to find his missing friends.
Sora and friends meet with Alice in this wacky World. Alice is one of the Seven Princesses of Heart and is being chased by the bellicose Queen of Hearts. Another characters introduced in this World are the Cheshire Cat, who likes to give riddles to Sora, Donald and Goofy, and the Talking Doorknob.
This is where Sora and friends meet Aladdin. The kingdom of Agrabah is in danger due to the ruthlessness of Jafar, the Royal Vizier, but after attempting to take over Agrabah using his final wish to become a genie, he is defeated by Sora and ends up sealed in a magical lamp.
In this World, Sora, Donald and Goofy meet with Cloud Strife from the Final Fantasy universe, and with Hercules. Cloud has been hired by Hades, the main antagonist in this world, to defeat Hercules in a tournament, but his plan ends up in failure. Sora will fight Cerberus, the Ice Titan and the Rock Titan in the Olympus Coliseum. Phil is introduced in here too.
Upon arriving to Deep Jungle, the junior heroes meet with Tarzan and help him fight the heartless that Clayton was controlling. Sora defeats him and gains the trust of Kerchak, who didn't trust in the humans that Tarzan had befriended.
Neverland is the world where Peter Pan lives. Wendy has been kidnapped by Captain Hook, who mistook her for one of the Seven Princesses of Heart, and Peter Pan, along with Sora and friends, defeat him to rescue Wendy. After defeating Captain Hook, Peter Pan asks Sora to look after Tinker Bell and then she can be summoned to aid Sora in battles.
Hollow Bastion is an original world created for Kingdom Hearts. It was once a peaceful kingdom called the Radiant Garden, ruled by Ansem the Wise. In his thirst for knowledge, he began studying the darkness in people's hearts, with six apprentices, including Xehanort. Ansem grew wary of the experiments and stopped them. Without his knowledge, his apprentices continued his work, producing the Heartless from hearts that were overwhelmed by darkness. A chain of events led to Ansem's banishment, Xehanort splitting into two beings, and the world being overrun by the Heartless. Deserted, the castle was later adopted by Maleficent as a headquarters. Most of the characters from the Final Fantasy universe, such as Squall (under the name "Leon"), Yuffie, Aerith, Cid, Cloud, Tifa, Sephiroth, Yuna, Rikku and Paine appear as residents of this World.
Halloween Town is an eternally dark village featured in all three of the main Kingdom Hearts games. It is based on Tim Burton's The Nightmare Before Christmas. The residents of Halloween Town are obsessed with their holiday and, each year, seek to outdo the last year's celebration. Though it has a mayor, the de facto leader of Halloween Town is the Pumpkin King, Jack Skellington. Sora, Donald and Goofy disguise themselves as spooky characters to blend in with the Halloween Town folk. The main antagonist in this world is Oogie Boogie, who attempts to take over Halloween Town by sending Lock, Shock and Barrel to steal the heart that Dr. Finklestein had created, but is defeated by Sora and friends.
Monstro is a world from Pinocchio. Monstro is not a world himself and because of that, it has no keyhole. His belly is large enough to serve as a world, filled with Heartless. Monstro swims through the dimensional rift between worlds as if it were water, attacking and swallowing any vessel that passes his way. Monstro escaped from the world of Geppetto and Pinocchio just before it was destroyed by the Heartless, and Geppetto finds himself inside Monstro looking for his "son", Pinocchio.
100 Acre Wood:
The 100 Acre Wood is a small world that can be found in the Winnie The Pooh book in Merlin's house. Sora must retrieve the missing five pages to unlock new chapters in the story and be able to enter the 100 Acre Wood inhabitants' homes and take part in the minigames and win prizes. There are no Heartless in this world.
In Atlantica, Sora and his friends are turned into sea creatures. Sora gets a dolphin tail, goofy is transformed in a turtle and Donald gets octopus tentacles. Atlantica is an underwater kingdom featured in all three of the main Kingdom Hearts games. Ruled by King Triton, its inhabitants are mermaids and sea creatures. Here, Sora will meet Ariel, a curious mermaid, and the youngest of the daughters of King Triton. She is fascinated by the human world and loves to collect objects from it. In this world, a more sinister area of the sea can be accessed: the Den of Tides and the sea witch Ursula's lair.
End of the World:
End of the World is the final world in the first Kingdom Hearts game. This world is made out of the worlds that lost their hearts to the Heartless. It is also the home of Chernabog, the huge winged demon from the Fantasia segment "Night on Bald Mountain". Director Tetsuya Nomura has called it the "Heartless" of worlds. The World Terminus is also located here, which gives the Heartless access to the corridors of darkness leading to other worlds.