A masterpiece of natural processes over eons of time, this vast network of limestone caves (the longest in Africa) from the Miocene Era illustrates the infinite variety of spaces and structures that can be created by the simple process of erosion. Continuous, minute change has characterized this site before its discovery by man. In the twelfth century, an Islamic holy man occupied it as a refuge. In the present day, Sof Omar is used for Muslim religious practices and is visited in pilgrimages by the faithful. Each cave structure and eroded room is uniquely named—the “Chamber of Columns,” the “Great Dome,” the “Mud Walk Chamber,” “Bat Shit Passage”¬—to mention a few of the better known features. A visitor to these mysterious caves—led by a guide with a flash light—will see arched portals, flying buttresses, airy vaults, and echo chambers connected to each other by narrow passages and the Weib River, which continues its sculptural path in perpetuity.