This Air Traffic map is a beautiful visualization of aircraft routes around the world. The map simply plots all international and domestic passenger air routes across the globe using green lines on a black background.
Simply by plotting international and domestic flights a fairly clear map of the world emerges. Africa and North & South America can be distinctly seen in the air traffic data. The intense traffic in Europe leads to a fuzzier picture but it is still possible to make out individual countries. If you zoom in on the map you can even identify individual airports on the map.