The south pole of the Moon is pretty intriguing. There are craters there that are deep enough that sunlight never reaches the bottom, because the Sun is always very low in the sky.
This has inspired some scientists to wonder if there might be water ice there. Comet impacts on the Moon, for example, could distribute water all over the surface. UV light from the Sun would quickly destroy the water molecules, but not if the sunlight can't reach it! So it's speculated there might be ice located at the south pole, deep in the permanent lunar antarctic shadow. Different observations have looked for it, but nothing conclusive has been found. People are eager to find it because finding water on the Moon could make it a lot easier for future colonists; hauling water up there is pretty tough. Water is heavy.
To aid future explorers, NASA has released the highest resolution radar images of the lunar south pole yet obtained. From this, they have been able to determine the topology of the surface there; that is, get accurate heights and depths of crater walls and crater floors. From that, and knowing the Sun's elevation over the pole, they have been able to make this totally awesome video [edited to add, link now fixed] showing what shadows and illumination look like there over the course of a lunar day, a little over 29 days long.
Cool, huh? Now play it again, and watch the craters near the bottom of the frame. See how the floors of some of them are dark all day long? That's where the Sun don't shine, as they say, and where there might -- might -- be ice. No one knows for sure if it's there or not. But aided with maps like this, future missions planned that will make better maps, and, of course, human exploration of the lunar surface, we'll find out.