South America at night. Satellite image of the Earth at night, set against a background of stars, centred on the continent of South America. North is at top. City lights (yellow) show areas of dense population. The highest concentrations of population are on the south-eastern coast, in cities such as Rio de Janeiro, Sao Paulo, and Buenos Aires. Large cities are also seen on the north-western coast. The large dark area (upper centre) is the sparsely populated and undeveloped Amazon rainforest. South America is relatively undeveloped compared to the bright lights of North America (top left), seen beyond the Caribbean islands. Image data obtained in 2001 by the Defense Meteorological Satellite Program (DMSP).