NAIROBI, Kenya — The Dadaab refugee camps in northern Kenya sit in a bleak landscape; remote, dusty and arid, they are sun-scorched by day and whipped by fierce dust storms that blow up seemingly out of nowhere.

The first three camps were opened in the early 1990s, when the civil war in Somalia brought thousands streaming across the border. Two more camps have since mushroomed out of the desert. In total they are home to about 500,000 people, making them the largest refugee complex in the world.

Proximity to Somalia makes Dadaab a sometimes dangerous place. Several aid workers have been kidnapped there in recent years, including two seized in 2011 who were freed only this summer. One incident ended last year in a shoot-out between kidnappers and Kenyan soldiers. Read more