Sometimes the best geography lessons can be learned from space.

This image, taken at night from a defense satellite orbiting at an altitude of 450 miles, shows the lights of cities in the Far East. North and South Korea are in the middle of the image, China on the left, and Japan on the right. The brightness of the lights correlates well with population density. The huge cities of Seoul, South Korea, Beijing, China, and Tokyo, Japan are very obvious. At the other extreme, it's hard not to notice that North Korea is almost completely dark, even though its population is nearly half that of South Korea. Very difficult political and economic times have dimmed the lights in this part of Asia.

One other note: the spots of light in the Sea of Japan are, believe it or not, fishing vessels, which try to attract squid using bright lights.