They often start out as temporary shelters for people fleeing war, food shortages and famine - but then spread out to become massive refugee camps.
In a new series - A Life Displaced - Al Jazeera takes a closer look at the plight of refugees worldwide, starting in Jordan.
The Zaatari refugee camp is home to 80,000 refugees from the war in neighbouring Syria.
Al Jazeera's Bernard Smith reports.
