NASA photos: Cities at night

To an observer in space, humanity’s footprint on the surface of the Earth is large and varied. Astronauts circling the Earth have the wonderful vantage point of observing the nighttime Earth. From 350-400 kilometers above the surface, they can take in whole regions at once. Onboard cameras and a bit of experimentation allow astronauts to take highly detailed images of our cities at night and share them with the rest of us.