Rainbow Mountains, Zhangye National Geopark, China: The Rainbow Mountains are cretaceous sandstones and siltstones that were deposited in China before the Himalayan Mountains were formed. The sand and silt was deposited with iron and trace minerals that provided it with the key ingredient to form the colors we see today....Known for its colorful rock formations, Zhangye National Geopark is located in Sunan and Linze counties within the prefecture-level city of Zhangye, in Gansu, China. It covers an area of 322 square kilometres. Wikipedia









