Are maria flat surfaces on the moon?
The maria (singular mare) appear relatively flat when viewed through earth-based telescopes. They are actually pitted with smaller craters and the surface of the maria are very uneven, very much like the rolling hills we see here on earth. They are far from flat.
The dark flat areas on the moon's surface are called Maria. The singular form of Maria is mare, which means sea. Although there are no seas on the moon, this is the term used to describe these darker areas. Approximately 16 percent of the moon' surface is covered with Maria. Most of these Maria are visible on the near-side of the moon.