In March 2011, a group of young boys in Dara'a, a city in southern Syria, felt inspired by the vibrant protests that had taken over the Arab World and toppled rulers in Egypt and Tunisia. Frustrated with the authoritarian regime of Syrian President Bashar Assad, the boys voiced their anger on one of the city's walls. "The people want the downfall of the regime," they spray-painted. Little did they know that one small act of defiance would spark a years-long, bloody conflict.
The United Nations has estimated that more than 70,000 people have lost their lives since the start of the protests in Syria, now two years ago. About 5,000 Syrians flee the country every day, seeking shelter in Jordan, Turkey, Lebanon and Iraq. According to Reuters, if the exodus continues at this rate, the number of refugees could exceed 1 million by the end of June.
HuffPost World looks back at 24 months of conflict in Syria in 24 strong photos. From the start of the mass protests in the spring of 2011, to the siege of Homs and the battle for Aleppo. Take a look at these powerful images and follow the rising monthly death toll in the slideshow below.