in northern Tanzania, the volcanic ash that belched out during the seismic past created the rich soils that today nourish one of the world’s great grasslands: the world-famous . This vast savannah has become the definitive picture-book landscape of Africa. On my first visit, I was — like most visitors — gobsmacked by the sheer sense of scale: not just the uncountable masses of blue wildebeest and zebra, which munch their way clockwise around the park in a ceaseless annual migration, but also the landscape itself, with its scudding cloud shadows turning the grasslands into an apparent ocean.
