Official NASA image of Earth lights during night (in nov 2000).
High res image:
One might wonder how could it be night at the same time throughout the Earth . But it is not a single image taken in one snapshot. It is a superimposition of thousands of satellite images which were taken when it was over each region.
Now, lets observe some interesting insights. Notice India uniformly illuminated (Even US is not so uniform). There certianly are some dark regions because of deserts and forests. But compared to other countries, India is more uniform mainly because of the population density.
Japan appears to be burning (so bright). Notice how bright the edges are at seashore in Europe. It shows how much the Europeans relied on trading (sea routes) and built their civilization by establishing port cities.
Notice the stark difference between North & South Korea.
As expected, the lights are bright at rivers due to major settlements around rivers (Nile in Africa & Indus in Ind/Pak).