Barcelona super star Lionel Messi has opened up on his sadness at the six years of war in Syria which has blighted countless lives.The Barcelona forward used his Facebook page to raise awareness of UNICEF's humanitarian campaign in the country."A war day is too much. The children of Syria have been subjected to violence and cruelty for SIX years in a conflict that holds them hostage. "As a father and as a UNICEF's Ambassador I am heartbroken. Add your voice to UNICEF to demand the end of the war." said the Argentine skipper.The Syrian Civil War is an armed conflict taking place in Syria. The unrest in Syria, part of a wider wave of 2011 Arab Spring protests, grew out of discontent with the repressive Assad government and poverty, and escalated to armed conflict after President Bashar al-Assad's government violently repressed protests calling for his removal.The war is being fought by several factions: the Syrian government and its allies, a loose alliance of Sunni Arab rebel groups (including the Free Syrian Army), the majority-Kurdish Syrian Democratic Forces (SDF), Salafi jihadist groups (including al-Nusra Front) who sometimes cooperate with the Sunni rebel groups, and the Islamic State of Iraq and the Levant (ISIL).