Zhangye Danxia National Geopark, Gansu, China
© TONNAJA/Getty Image
Walking a rocky rainbow. International Rock Day
International Rock Day is celebrated on July 13. Why do rocks need a day of recognition? Because these hardy heroes have played a big part in human history since the Stone Age. They served as humanity's first tools and as nature's journals, carrying fossils of ancient organisms and documenting changes in geological processes. A great example of the latter is Zhangye National Geopark's Rainbow Mountains in China. This geological wonder displays vivid colours: reds, oranges, yellows, and purples, which are layers of sedimentary sandstone rock. These unique mountains were formed through erosion over millions of years, creating the patterns and colours that define this landscape. No matter what your favourite category of rock is—metamorphic, sedimentary, or igneous—rocks of every kind helped build the world we live in today.
Blue walls of Chefchaouen, Morocco
Abstract motion blur of aspen trees in Kluane National Park, Yukon
A carving of artist W.O.J. Nieuwenkamp in the Pura Meduwe Karang temple in Bali, Indonesia
Members of the Wild Red Flame Mardi Gras Indians in New Orleans, Louisiana
Street art from the Pasadena Chalk Festival 2013, Pasadena, California
The National Wallace Monument overlooking Stirling in Scotland
Mars Express image of the icy cap at Mars’ south pole
The Lush Rainforest of Cathedral Grove, Macmillan Provincial Park, B.C.
