View larger/full image. | This color-coded topographic map from ESA’s Mars Express orbiter shows part of what used to be a massive lake (in blue), called Lake Eridania by earthly scientists. It’s in the Caralis Chaos region on Mars. It appears to have been the largest Mars lake, bigger than any known earthly lake. Image via ESA/ DLR/ FU Berlin (CC BY-SA 3.0 IGO).
- Mars had lakes billions of years ago. They eventually dried up and disappeared when Mars’ climate became too cold and its atmosphere too thin to support liquid water.