The Moon has a near side and a far side. The side that permanently faces the Earth is known as the near side while the side that faces away is known as the far side. Though these sides are so, the amount of sunlight they receive is almost the same.
The surface of the near side differs from the far side; the near side is covered by large patches of dark areas. Early scientists proposed that these dark areas were seas with water. The dark patches are still known as seas. The far side does not have such seas. The crust here is thicker than the side facing the Earth.
Picture Credit : Google