Geological and mineralogical evidence suggests that approximately four billion years ago, Mars was warm and wet enough to support abundant liquid water on its surface, ranging from rivers and lakes to a vast northern sea. This period spans two geological eras: the Noachian, which lasted from 4.1 to 3.7 billion years ago, and the Hesperian, which lasted from 3.7 to approximately 3 billion years ago. The Noachian era is characterized by warmer conditions, but in its final stages, Mars would have begun to cool as it steadily lost its atmosphere to space.