File - In this Friday, March 18, 2011 file photo, an anti-government protestor reacts as others carry a wounded protestor from the site of clashes with security forces in Sanaa, Yemen. Ten years ago, an uprising in Tunisia opened the way for a wave of popular revolts against authoritarian rulers across the Middle East known as the Arab Spring. For a brief window as leaders fell, it seemed the move toward greater democracy was irreversible. Instead, the region saw its most destructive decade of the modern era. Syria, Yemen, Libya and Iraq have been torn apart by wars, displacement and humanitarian crisis. (AP Photo/Muhammed Muheisen)