A U.S. Air Force plane takes off as a Turkish air force fighter jet taxis at the Incirlik airbase, southern Turkey, in 2013. Reversing an earlier policy, Ankara has agreed to allow the U.S.-led coalition to fly anti-ISIS airstrikes from the base. Vadim Ghirda/AP hide caption

itoggle caption Vadim Ghirda/AP

"What we are doing now has nothing to do with what we expected to be doing," says Rami Jarrah, who protested against the Assad regime in Damascus in 2011 and now runs a radio station from southern Turkey that broadcasts to civilians in rebel-controlled territory in northern Syria. Alison Meuse/NPR hide caption

itoggle caption Alison Meuse/NPR

Saeed al-Batal, a Syrian photographer, posted this image from Douma, Syria, on his Facebook page on March 31. Courtesy of Saeed al-Batal hide caption

itoggle caption Courtesy of Saeed al-Batal

Malala Yousafzai celebrated her birthday and the opening of a new school with "brave and inspiring girls of Syria" in Lebanon on Sunday. WAEL HAMZEH/EPA /LANDOV hide caption

itoggle caption WAEL HAMZEH/EPA /LANDOV

Refugees from Syria arrive in Presevo, near the border with Macedonia, in the south of Serbia, on Wednesday. The U.N. says more than 4 million have fled the civil war in Syria, making it the worst refugee crisis in a quarter century. Djordje Savic/EPA/Landov hide caption

itoggle caption Djordje Savic/EPA/Landov

Syrian Kurds from Kobani wait behind the border fences to cross into Turkey on Friday. An attack by Islamic State fighters on the Syrian town of Kobani and a nearby village has so far killed at least 146 civilians, the second-biggest massacre by the hardline group in the country, a conflict monitor said on Friday. Murad Sezer/Reuters/Landov hide caption

itoggle caption Murad Sezer/Reuters/Landov

Mohammad and Linda Jomaa al-Halabi, along with their five daughters, are among the fewer than 1,000 Syrian refugees who have been resettled in the U.S. They left Syria in August 2012 and arrived last year in Baltimore, where they live now. Michele Kelemen/NPR hide caption

itoggle caption Michele Kelemen/NPR

Mourners attend the May 14 funeral of Hezbollah fighter Ahmad al-Amin in Babliyeh, Lebanon. Hezbollah is fighting alongside the Syrian army and Amin was killed while fighting in Syria's Qalamoun mountains against Nusra Front, al-Qaida's branch in Syria. The Syrian army has suffered multiple setbacks recently, but Hezbollah did help dislodge rebel fighters along the Syria-Lebanon border. Mohammad Zaatari/AP hide caption

itoggle caption Mohammad Zaatari/AP

In this photo released Thursday by a website run by Islamic State militants, damaged Syrian helicopters sit at Palmyra air base, which was captured by ISIS after a battle with the Syrian government forces earlier this week. Uncredited/AP hide caption

itoggle caption Uncredited/AP

A photo released on Sunday by the Syrian official news agency SANA shows a general view of the ancient Roman city of Palmyra, northeast of Damascus, Syria. Fears have intensified that the self-declared Islamic State, which captured the city on Wednesday, might raze the ruins. AP hide caption

itoggle caption AP

Smoke rises after a Syrian Rocket launcher shell on Islamic State positions in the ancient oasis city of Palmyra, about 215 kilometers northeast of Damascus on Tuesday. News reports say the Islamic State has taken control of the city. EPA /Landov hide caption

itoggle caption EPA /Landov

Columns in the courtyard of the temple of Baal in the ancient city of Palmyra are damaged by the shelling in this March 14, 2014, photograph. Joseph Eid/AFP/Getty Images hide caption

itoggle caption Joseph Eid/AFP/Getty Images

People gather around a helicopter reportedly belonging to Syrian government forces that crashed in March in Jabal al-Zawiya in northwest Syria. Islamist rebels captured four crew members, while a fifth was killed, according to the Syrian Observatory for Human Rights. Opposition fighters have made a number of advances in recent weeks. Ghaith Omran/AFP/Getty Images hide caption

itoggle caption Ghaith Omran/AFP/Getty Images