The lunar maria are large, dark, basaltic plains, formed by ancient volcanic eruptions
If you have a good imagination there is a shape on the full Moon which looks like Mary and child.
Maria is a bunch of Basaltic material (which is igneous rock) that came together on the moon. It formed when the moon cooled. People used to think that the dark spots (maria) on the moon were oceans.
the moon is not made of cheese
Maria is latin for sea. They are actually large basaltic lava flows from the period when the moon still had a molten core.
moons were made in early days before the dinosaurs were around by planets (rocks) clashing because they didn't have any gravity.