The World of Greyhawk is a fantasy campaign setting for the Dungeons & Dragons role-playing game, created by Gary Gygax in the 1970s. It features a rich tapestry of kingdoms, cultures, and deities, set in the continent of Oerik. Players can explore various regions, including the Flanaess, which is home to many adventures and conflicts. Greyhawk is known for its detailed geography and history, including notable locations like the City of Greyhawk and the Temple of Elemental Evil. The setting includes iconic characters such as Mordenkainen and Rary, who have become staples in the D&D universe.