Lebanon this week marked what the UN called a “devastating milestone”: one million Syrians have now registered for official refugee status there. Lebanon’s own population is just about four-and-a-half million, making it the country with the highest per capita concentration of refugees recorded anywhere in the world. The three-year-old Syrian conflict has created a massive humanitarian crisis. More than two-and-a-half million Syrians have sought refuge in neighboring countries.

Watch our report on Syrian refugees in Jordan.