Lake Nakuru is a shallow soda lake in the Great Rift Valley of Kenya, its water too caustic for fish, and for decades it was the place where more than a million flamingos turned the shoreline pink; today it is a fenced sanctuary for rhino and one of the last strongholds of the Rothschild's giraffe. The lake has no way out. Water flows in from the volcanic slopes around it but none flows out, so every mineral stays behind and concentrates, and the only thing that thrives in it is a blue-green algae called spirulina, which lesser flamingos filter through their beaks in their thousands. When the algae is blooming they still gather along the shallows in shifting bands of pink, wading and feeding; since the water began rising in 2010 the great flocks are no longer guaranteed, and may scatter to Lake Bogoria or Elementaita nearby, but great white pelicans gather here in the hundreds, drifting in tight rafts on the open water and lifting off together to fish.
The rising water has left its own mark: where the lake swallowed the old shoreline, whole stands of acacia now stand bleached and leafless in the shallows, a drowned forest that shows how fast Nakuru changes. The park around the lake is small enough to drive in a day and dense with animals. When poaching gutted Kenya's rhino numbers in the 1970s and 80s, Nakuru was fenced off in 1987 as one of the country's first rhino sanctuaries, and both black and white rhino are now seen out on the open grass by the shore; the rare Rothschild's giraffe, pale-legged and moved here for safety, step through the acacias, and lions and leopards use the trees. On the eastern slopes stands one of the largest forests of candelabra euphorbia in Africa, cactus-like trees up to 20 metres tall. Nakuru is a lake that has changed colour twice in a lifetime, from pink to grey to green, and the animals on its shore are why people still come.