The geographic cycle, or cycle of erosion, is an idealized model that explains the development of relief in landscapes.[1] The model starts with the erosion that follows uplift of land above a base level and ends, if conditions allow, in the formation of a peneplain.[1] Landscapes that show evidence of more than one cycle of erosion are termed "polycyclical".[1] The cycle of erosion and some of its associated concepts have, despite their popularity, been a subject of much criticism.