It has been 10 years since the war in Syria began. Hundreds of thousands of people have died over the past decade and tens of thousands have disappeared, their fates unknown. Russia and Iran, the US and its allies, and Turkey each back different competing groups - all of which have fought long, bitter battles to acquire the territory they hold. The war that has engulfed Syria shows no sign of ending for good.
Although there is a shaky ceasefire in place, the country remains what a UN monitor calls a "tinderbox" - with five foreign militaries poised and ready to engage in active operations.
This is the story of one of the most violent and bloody conflicts of the 21st century.