Syrian People's Protection Units (YPG) members sit in a tank in frontline of Raqqa, on January 7, 2016. YPG fight against the Daesh to liberate the city of Raqqa. (Photo by Jacob Simkin/NurPhoto via Getty Images)
Syrian People's Protection Units (YPG) members sit in a tank in frontline of Raqqa, on January 7, 2016. YPG fight against the Daesh to liberate the city of Raqqa. (Photo by Jacob Simkin/NurPhoto via Getty Images)