Rivers are tumultuous forces of life. Dragged by gravity across the Earth, they've carved the largest canyons and the most beautiful valleys of our planet.
Even the smallest stream is a complex ecosystem with plants, animals and ever-changing water. The flowing water also carries alluvium across its path. Alluvium is the soil and small rocks that are picked up as the river flows. If you were to stand in a slow-moving shallow stream, your feet would sink into the alluvium and you would feel the bits of sediment around your toes.
In some unique places in the world, a river reaches a flat plain and smaller streams fan out across the plain. Over time, the water deposits the alluvium, which stands out from the surrounding landscape. These unique formations, called alluvial fans, can range from the minuscule to the truly massive and the largest are often seen best from space, unique sculptures made by the Earth.
In the Kunlun and Altun mountain ranges of the Taklimakan desert in XinJiang, China, the largest alluvial fan in the world spans the desert: 56.6 kilometers wide and 61.3 kilometers long. Parts of the fan are blue, alive with the water flowing from the Molcha River.
Other large alluvial fans are found in Death Valley, California, Southern Iran, and the French Pyreenes.