Kambadaga Falls are a staircase of four cascades on the Kokoulo river near Pita, in the Fouta Djallon highlands of Guinea, dropping sixty metres in steps through a gorge of dark layered rock, and their wet ledges hold two plants known nowhere else on Earth, which flower in the open air for a few weeks each year as the river drops. The Fouta Djallon is the water tower of West Africa, a sandstone plateau where the Niger, the Senegal and the Gambia rise, and the Kokoulo has cut down through a hard cap of quartzite-rich sandstone into softer, older rock beneath, which is why the fall comes down in steps rather than one leap; above the drop the river spreads over broad sun-warmed slabs where people sit at the lip with the gorge opening below. Boulders at the bottom of the tallest step let visitors get right underneath the fall, where the water comes down in dozens of separate threads, and once the river has fallen after the rains a deep dark pool stands at the foot of the cascade, swum through the afternoon by the villagers.
The plants are the fall's secret. On the wet rock live crusts of river-weeds, plants of the Podostemaceae that grow only in the spray of waterfalls, and in 2018 botanists from Kew refound two of them here that were feared extinct in the world, Inversodicraea abbayesii among them, and described a third new to science, Saxicolella futa; the same plants once grew at Kinkon Falls, fifteen kilometres up the river, until a dam wiped them out, so Kambadaga is their last refuge. As the river drops the crusts are left in the air and flower within weeks, photographed in bloom in January. At the tail of the rains the Kokoulo spreads across the full hundred-metre lip and the four cascades run as one wall of water, when the ledges vanish and swimming is dangerous. Kambadaga is a waterfall in four steps, and the rarest things in it grow on the wet rock.