ISTANBUL, TURKEY - DECEMBER 23: Turkish security forces and firefighters take security measures after an explosion, at Sabiha Gokcen Airport in Istanbul, Turkey on December 23, 2015. Unknown explosion left 2 wounded airport worker, officials said. The cause of the explosion remains unknown on the early morning of the day. (Photo by Arif Hudaverdi Yaman/Anadolu Agency/Getty Images)
