Humans have created thousands of settlements, and we are lucky enough to be able to see some of them from the eyes of ISS astronauts. These images are incredibly difficult to take from a spacecraft traveling along at almost 28,000 kilometers per hour. The images are held at NASA's Johnson Space Center in a special archive for astronaut photography. Watch for the great cities of Mumbai, Rio de Janeiro, Mexico City, Johannesburg, New Delhi, Toronto, Sydney, and many others. All included population numbers are based on estimated metropolitan populations.