See the Surprising Ways Mars Has Changed in 3 Billion Years
▻https://www.nationalgeographic.com/science/2016/11/exploring-mars-map-panorama-pictures/?sf202620388=1
If #Mars explorers could literally step back 3.8 billion years, they would be walking on a warmer, gray world. The iron-rich soil had not yet rusted, and the planet was blanketed in a thicker atmosphere. Geologic clues suggest that Mars back then was covered with crater lakes, river valleys, and maybe even a large ocean in the northern hemisphere.
#eau