Artwork depicting Mars in three different epochs: the Noachian Period (4.1-3.7 GYa), the Hesperian (3.7-3.0 GYa) and the Amazonian (present). The Noachian Mars was a cold, snowy and watery world with rivers, lakes and small seas from melting snow. Similar to summer in Iceland. The great Valles Marineris was beginning to form, and the Tharsis volcanoes along with it. The Hesperian Period was more like Iceland in the winter, cold and icy with less liquid water. Valles Marineris was fully formed by this point, and the Tharsis volcanoes were nearing their modern configuration. Now, during the Amazonian, Mars is cold and dry with water ice at the caps and underground.