On the highway between Baku and Quba in Azerbaijan, a series of red-and-white striped peaks emerge suddenly from the surrounding landscape. Part of the Greater Caucasus mountain range, the Candy Cane Mountains earned their nickname thanks to their striking resemblance to the classic Christmas treat.

The color of these rocks is a product of the area’s unique geology. The Candy Cane Mountains are made of shale, a type of sedimentary rock made up of many thin layers stacked on top of each other. Long ago, before the rock was formed, changes in the environment led to differing mineral composition as the layers of sediment were deposited.

As the shale came in contact with water, layers that contained iron oxidized and turned red, while layers without iron remained shades of white and gray. Over time, tectonic movement and erosion have exposed these sedimentary layers into a visual representation of geologic history. The Candy Cane Mountains also contain many belemnites, fossils of an extinct order of squid-like creatures from the Cretaceous period.