As the Earth and Moon orbit around the Sun, there are places on the Moon that never receive direct sunlight. Most of these permanently shadowed regions are at the lunar poles. This animation approximates the permanently shadowed regions pertaining to the Moon’s south pole by maintaining a maximum sun angle to the surface of 1.5 degrees. These permanently shadowed areas are of interest because they could hold water ice. (Update: they do!)
The American, European, Japanese, Indian, and Chinese have placed orbitial spacecraft around the Moon in this decade. Many more missions are being planned to locate and taste the water now on the Moon and to determine how it may be used by humanity in future habitat construction.