When it rains, it pours in Nxai Pan in northern Botswana. Lush plains scattered with vast herds of antelope stretch to the horizon. It is a veritable paradise. But Nxai Pan is a place of harsh contradictions. For when the rainy season is over, the lake dries up, leaving behind only cracked, desiccated salt pans as the desert, and its devastating heat returns. The bigg...