When you come across unrealistically bright pictures from this geological site, you start suspecting Photoshop is involved. Unfortunately, many pictures may indeed be modified. Nonetheless, don't get disappointed too early, for the colours are there, just not that strikingly bright. And when you see the variety of hue shades, you'll admit the rocks are fairly called "Rainbow Mountains".
The first mountains began to rise up in the place of modern Gansu Zhangye National Geopark some 55 million years ago as a result of the Indian and Eurasian Plates collision. The colourful layers you see are deposits of sandstone and siltstone formed some 24 million years ago. Long years of rains and winds did the rest of the work, shaping smooth slopes beside sharp pinnacles, and various chemical processes led to the variety of paints we can observe today.
Since 2010 the geological wonder has been protected as UNESCO World Heritage Site, and every other year it draws more and more tourists from China and abroad.
The best season to explore the unique landforms is June through September. Unlike cold and windy winters, summer offers amiable weather which is not just more favourable for hiking but also allows to see the best of mountains' colours.
Sunsets are said to be gorgeous in China's Rainbow Mountains, so take it into account.