The Sahel (/səˈhɛl/) is the ecoclimatic and biogeographic zone of transition in Africa between the Sahara to the north and the Sudanian Savanna (historically known as the Sudan region) to the south. In the Sahel, abject poverty, fast population growth, climate change, recurrent food and nutrition crises, armed conflicts and violence converge dangerously. The chiefs of the Sahel grew rich from taxing traders.