Ethiopia is located at the northwestern corner of Africa, with a coast to the Red Sea. It has huge areas with sedimentary rock, typically Jurassic and Cretacious limestones. Many areas are karstified and the country has huge cave systems, the longest one is more than 15km long.
Several areas are covered by extensive layers of Tertiary and Quarternay volcanic rocks, with numerous volcanic caves. At the volcano Mt. Fantalo are the largest blister caves of the world were found. Some 130 blisters are known, where the still intact blisters are up to 30m in diameter, but the already collapsed ones are up to 100m.
Ethiopia has already very good positions in the longest caves of Africa list, but still it is very promising and many cave areas are not yet sufficiently investigated.