Imagine feeling unsafe all the time. Living in a constant state of fear.

An estimated 1/5 million people have perrised in this civil war. Imagine living in a country where every major city is a target for civil unrest and highly likely to be bombed at any moment. Half your city has been destroyed already. You would feel unsafe outside, and you would feel unsafe indoors. Nowhere is safe. Naturally, you would choose to leave.

http://www.nytimes.com/interactive/2015/09/14/world/middleeast/syria-war-deaths.html?_r=0