That's partially true! The Moon does have large flat plains, but they are not called "plains" in the scientific sense. They are called maria (singular: mare).

Here's why:

* Maria are not plains: They are actually vast, dark, smooth areas formed by ancient volcanic eruptions.

* Volcanic origin: Billions of years ago, volcanic activity on the Moon spewed lava that flowed across the surface, creating these smooth, flat areas.

* Appearance: From Earth, maria appear as darker patches on the Moon's surface, contrasting with the lighter, cratered highlands.

So, while the Moon does have large flat areas, they are not called "plains" and have a different geological origin.