The Mushroom Kingdom is the primary setting of the Mario franchise. It is ruled by Princess Peach, and its appearance changes from game to game. Despite this, the kingdom consists of many similar recurring landscapes, such as plains, deserts, islands, forests, mountains, snowy areas, and volcanoes. In the mainline Mario series, the Mushroom Kingdom is frequently invaded by Bowser, but there have been other disruptions such as by the Dark Star, the Blorbs, and the Shroobs. Most of these incidents involve Peach's kidnapping, after which Mario, Luigi, and other allies cooperate to rescue her. Sometimes, usually in the Mario RPGs, the villain even overtakes Bowser, leading Bowser to ally with Mario and Luigi to rescue Princess Peach. In other cases, Princess Peach is not kidnapped (such as in the Mario cartoons), or she is quickly rescued and she assists Mario and friends to save the kingdom from the villains.