A chaotic region is a distinctive area of fractured and disintegrated terrain. It is characterized by a textured matrix featuring randomly orientated flat-topped mesas, knobs of various sizes, and deep depressions. Chaoses are primarily found on Mars in regions unofficially called “chaotic terrains.” The latter is located east of Valles Marineris and involves parts of the huge outflow channel floors. Various processes are suggested to have formed the Martian chaoses, including disruption and collapse of an icy permafrost layer initiated by pressurized groundwater, the action of aqueous processes, and multiple episodes of nested surface collapses caused by the removal of subsurface material, either ground ice or magma. Chaos regions can also be found on Jupiter’s moon Europa, which is suggested to be sites of melt-through from the subsurface.