Ethiopia is a land of diverse geological formations. In some parts of the country, volcanic rock dominates, but, in others, sedimentary rock dominates, including limestone. This is where caves can sometimes be found. The most well-known cave in Ethiopia is Holga Sof Omar is one of the most spectacular and extensive cave systems in the world.

A vast underworld has been created by the Weyib River’s erosion of limestone rock formations. The system is located east of Robe, which follows the river down from the Bale Mountains. After passing Goro, the village of Sof Omar is reached. Two of the useful entrances of the 15.1km system are here. The route through the cave from here crosses the river eight times. From the second ford, the most spectacular view of the cave can been seen, known as Safari Straight. Crossing all eight fords leads to the grand Chamber of Columns. After, that is another interesting feature called the Big Rapids, after which another main entrance is reached, known as the Holuca Resurgence. The caves are also an important Islamic shrine named after Sheikh Sof Omar Ahmed from the 11th century AD.