Palestinian boys at a damaged building in Rafah, the Gaza Strip, on Thursday. U.S. attempts to broker a comprehensive peace deal have again been shelved as Israel and Hamas have waged their third round of heavy fighting in Gaza in the past six years. Ibrahim Khatib/Barcroft Media/Landov hide caption

itoggle caption Ibrahim Khatib/Barcroft Media/Landov

This handout photo provided by the Office of the Defense Secretary (OSD), taken Aug. 19, 2014, shows a Chinese fighter jet that the White House said Friday conducted a "dangerous intercept" of a U.S. Navy surveillance and reconnaissance aircraft. Uncredited/AP hide caption

itoggle caption Uncredited/AP

Peshmerga fighters inspect the remains of a car bearing an image of the trademark jihadist flag, after it was targeted by an American airstrike in the village of Baqouba, north of Mosul. The car reportedly belonged to Islamic State militants Ahmad Al-Rubaye /AFP/Getty Images hide caption

itoggle caption Ahmad Al-Rubaye /AFP/Getty Images

Vance, who serves as a coach, founded the group after his own struggle with PTSD. He says it helped him get out of a dark place. He now has a degree in social work. David Gilkey/NPR hide caption

itoggle caption David Gilkey/NPR

A U.S. Navy P-8 Poseidon aircraft takes off from Perth International Airport during the search for Malaysia Airlines MH370. The same general type of aircraft was involved in a "dangerous intercept" by a Chinese fighter jet earlier this week off Hainan island. Reuters/Landov hide caption

itoggle caption Reuters/Landov

Secretary of Defense Chuck Hagel (left) and Chairman of the Joint Chiefs of Staff Gen. Martin Dempsey during a Pentagon briefing on Thursday. Hagel said Islamic State militants in Iraq and Syria posed a threat "beyond anything we've seen." Yuri Gripas/Reuters/Landov hide caption

itoggle caption Yuri Gripas/Reuters/Landov

Mark Pierce enlisted in the military in 1970, served in Vietnam and retired in 2010. Years later, his two sons also joined the armed forces. Courtesy of Mark Pierce hide caption

itoggle caption Courtesy of Mark Pierce

Forces loyal to Syria's President Bashar Assad walk along a street in Mleiha, near the Damascus airport, during a tour organized by the Syrian government on Aug. 15. Omar Sanadiki/Reuters/Landov hide caption

itoggle caption Omar Sanadiki/Reuters/Landov