Planet Aries (アリエス星), also known as Miracle World, is the homeplanet of Alex Kidd. In Alex Kidd in Miracle World, only the kingdom of Radaxian and the Kingdom of Nibana are shown in this planet.
Although Aries is a planet, it is not the only planet shown in this universe. There is also the planet Janbarik (Paperock), where Janken the Great and his minions have come from.
Miracle World in Worlds Unite