4. Sof Omar Cave
Considered the longest system of caves in Africa, Sof Omar Cave is found in the Bale Zone of the Oromia Region in southeastern Ethiopia. It is estimated to be 15.1 kilometers long and starts from Ayiew Maco and ends at Holuca.
According to locals, the cave is named after a Muslim holy man who lived in the area hundreds of years ago. The cave is a sacred place for both Islam and the local Oromo traditional religions. The cave is known for its many pillars, especially the “Chambers of Columns.”