The Lunar Reconnaissance Orbiter (LRO) has been circling the moon since 2009.
Recently NASA combined a series of images from the LRO camera to create a movie of a rotating moon, allowing those of us back on Earth to see the moon from every side, including the dark side.
Only one side of the moon is visible from Earth.
The side we cannot see is nicknamed the 'dark side'.
The moon is 'locked' into position relative to the Earth because a complete rotation on the moon's axis takes 29 days.
These 29 days also happen to be the length of time it takes the moon to make a circle around the Earth.
It is the combination of these two rotations that keeps one side of the moon facing Earth at all times.
The below graphic from ScienceBlogs shows the process.