Cities of Earth is a free beautiful 3D screensaver which shows biggest cities of our planet.

Features:
Aflame Sun, stars, 3D Earth model with highlighted cities.
Many of cities with information about its population and country names. So it's a good educational content. The positions of all cities corresponds to its real world coordinates.
Day gives place to a night and vice versa.
Displaying of local cities time
Low CPU usage.
Zoom in/zoom out: Use mouse wheel to move comera closer/farther.
Camera Control: Use "up" and "down" arrow keys to control the vertical camera position (e.g. to look at Antarctica). Use "left" and "right" arrow keys to slow down or to speed up the camera rotation speed.