The world setting is Earth, but in a fictionalized Antediluvian Age (a quasi-historical/mythical interpretation of the ancient past).
Geography
The geographic regions and real-world influences are: Mediterranea (Europe), Eria (North America), Tamoanchan (South America), Turan (Arabia), Gondwana (Africa), Jambu (Asia), the Nether Realm (Antarctica), and Anostos and Jotunland (Iceland and Greenland-like). Mythical continents are added: Atlantia (Atlantis), Antilla, Hyperborea, Lemuria, Mu, and others.
Source: Wikipedia, "(role-playing game)", available under the CC-BY-SA License.