The U.S. backed the country in its independence struggle. Now, it is needed again.
The jihadi group has displaced more than 2 million people across northeast Nigeria and neighboring countries.
Almost half the population face food shortages and 100,000 people are at risk of immediate starvation in South Sudan.
At least 82 aid workers have been killed since 2013 in South Sudan, the U.N. says.
Some 16 million people in the region are in urgent need of food, water and healthcare.
Somalia is at risk of another deadly famine, six years after the last killed 250,000 people.
Food has long been used as an instrument of power, one that lets populations live or die.
A look at why today's U.N appeals have trebled since 2005's $5 billion.
The U.N. has also expressed fears over the country’s food security.
In Ethiopia, endemic crop diversity could be key to averting a future of food scarcity.