The UN oversees refugee movements around the world. When people are no longer safe in their homes due to war or persecution, some decide to undertake a dangerous, often life-threatening journey to a neighboring country. Upon arrival, they register with a camp run by the UN. They then undergo a screening process that includes bio-metric data collection and face-to-face interviews. The process to be cleared by the UN takes anywhere from a few months to a few years. The average length of stay in a refugee camp is 5-7 years. Refugees admitted to the US are vetted by the Department of Homeland Security with further interviews and bio-metric data checks. This process takes between one and two years.