They were formed at least 100 million years ago along a fault lying to the east of the East African Rift, which is a more recent structure. About 30 million years ago, all this area was covered by extensive rainforest.
At least 100 million years ago, these formations were created along a fault that lies east of the East African Rift, an older structure compared to today's configuration. Around 30 million years ago, all this region was enveloped in extensive rainforest.