Maria (lunar geography)

Maria are large, dark, flat plains on the Moon's surface formed by ancient volcanic activity. Their smooth appearance results from basaltic lava flows that filled impact basins billions of years ago. These basalt plains are less cratered than surrounding highlands, making them easier to identify. Maria are primarily found on the lunar near side, facing Earth, and cover about 16% of the lunar surface. They provide valuable insights into the Moon’s volcanic history and are notable features for lunar exploration and study.