Lake Natron lies in the Rift Valley close to the Kenyan border, shallow and intensely alkaline — caustic enough that few organisms tolerate it. The water can reach temperatures above 40°C and takes on deep reds and oranges from salt-loving microorganisms, which is what produces the aerial images the lake is famous for.
That hostility is exactly why it matters. Lesser flamingos breed on its salt flats almost undisturbed by predators, and Natron is the principal breeding site for the species in East Africa — the great majority of the regional population hatches here.
Above the lake stands Ol Doinyo Lengai, the Mountain of God in Maasai, the only active volcano on earth erupting natrocarbonatite lava, which is cool enough to appear black in daylight. It can be climbed overnight, a demanding ascent usually started around midnight to summit at dawn.