Inside Aleppo: the underground schools sheltering children

The children of Aleppo have been some of the biggest casualties of the war. It's the beginning of the school year - and according to the Children's charity UNICEF, one in three schools in Syria are out of action because they've either been destroyed by airstrikes or are being used in the fighting. Since the war began five years ago, there have been over 4000 attacks on schools across the country. In East Aleppo, thousands of children are staying away from class, but for those brave enough to go, they are having to go underground for an education.