In geography, a plain is an area of lan with relatively low relief — meaning that it is flat. Prairies and steppes are types of plains, and the archetype for a plain is often thought of as a grassland, but plains in their natural state may also be covered in shrublands, woodland and forest, or vegetation may be absent in the case of sandy or stony plains in hot deserts. Types of flatlands for which the term is not generally used include those covered entirely and permanently by swamps, marshes, playas, or ice sheets.