Mare (lunar surface feature)

Mare, also known as lunar maria, are large, dark, flat plains on the Moon's surface formed from ancient volcanic eruptions. These basaltic plains are created when lava from the Moon’s interior flowed into impact basins, solidified, and cooled, resulting in smooth areas that contrast with the lighter, heavily cratered highlands. The maria cover about 16% of the moon's surface and are generally younger than the highlands. They appear darker due to their basaltic composition, and their study helps scientists understand the Moon's volcanic history and geological evolution.