Classify photos taken by astronauts on the International Space Station to create a map of light pollution around the world. Light pollution is artificial light (such as street lamps) that results in masking the cosmos in the night sky, making it difficult to see the stars that would otherwise naturally appear to the naked eye. Light pollution is bad not only because it blocks our ability to see the Milky Way, but it can also disrupt natural ecosystems. The Cities at Night project needs volunteers to help sort and identify the location of pictures taken of the Earth at night. The resulting maps will assist governments and local authorities in making decisions to reduce light pollution.