Google Earth has three new layers from NASA (you can find them in the Featured Content folder): astronaut photos of the Earth, satellite imagery for geographic phenomena like the tsunami from 2004 that devastated countries around the Indian Ocean and Earth City Lights, a layer that shows the intensity of light at night for all the cities in the world. Here's a part of Europe and some context:
"The brightest areas of the Earth are the most urbanized, but not necessarily the most populated. (Compare western Europe with China and India.) Cities tend to grow along coastlines and transportation networks. Even without the underlying map, the outlines of many continents would still be visible. (...) Even more than 100 years after the invention of the electric light, some regions remain thinly populated and unlit. Antarctica is entirely dark. The interior jungles of Africa and South America are mostly dark, but lights are beginning to appear there," says NASA about the layer.