Wired Science has a fascinating series of rivers photographed from space.  Pictured above is Rio Negro, in Argentina.

The Rio Negro in Argentina is a beautiful example of how mobile some rivers are. This is one of the most meandering rivers in South America. In the image above, taken by astronauts aboard the International Space Station on January 4, the river has left scars all across the floodplain as it moved and carved new channels. Some of the old river channels still have water in them and are known as oxbow lakes.

via Channeling Earth: Rivers Seen From Space | Wired Science | Wired.com.