The darker areas are known as maria (singular mare, Latin for sea), though they have never seen a drop of water in the last four billion years. The lighter areas are mostly cratered highlands, where relatively recent asteroids have crashed into the moon's surface, exposing bright rock beneath the surface.

The largest dark area on the moon, on the left side, is actually called an "ocean": the Oceanus Procellarum or Ocean of Storms. Just above it, and almost as large, is the Mare Imbrium or Sea of Showers. Opposite Imbrium on the right side of the moon is a triangle of three smaller "seas": the Mare Serenitatis (Sea of Serenity), Mare Tranquillitatis (Sea of Tranquility) and Mare Crisium (Sea of Crises).

Although there are smaller seas, most of the rest of the moon's near side is highlands, covered with hundreds of craters. By far the most prominent of these is Tycho, named for Tycho Brahe, the greatest astronomer of the sixteenth century. This crater is brilliantly white, and is the source of a huge system of rays: bright linear features which encircle the globe of the moon. The Tycho ray system, along with several smaller ray systems, are best seen when the moon is full.