If you ever wanted to gaze down on our planet from space, try Cities of Earth 3D Free Screensaver. The screensaver features our planet revolving at the speed it actually does. It is particularly curious that it lets you see the Earth just as it looks like now, the moment you are running the program. You’ll also be able to see the world’s largest cities marked with bright spots. There is also a zoom in/ out function, which lets you see the planet much closer.