The mountain is shaped a bit like a long ridge, with grassy highlands near the top and thick forest lower down. Because it rises so high, it creates its own small climate - it is cooler and mistier up top, which means completely different plants and animals live there compared with the hot lowlands below.
Mount Nimba is famous among scientists for its unique wildlife. It is one of the few places in the world where a special kind of chimpanzee has been seen using rock tools to crack open nuts - a behaviour that took researchers completely by surprise when they first filmed it.
The mountain's streams flow outwards in three directions, feeding rivers in all three surrounding countries. A raindrop landing on the very peak could end up in Liberia, Guinea or Côte d'Ivoire - it all depends on which side of the summit it falls. That makes Mount Nimba a natural water tower for the whole region.