A man walks past the rubble of a building following reported shelling by Syrian government forces in the Bab al-Hadid neighbourhood of the northern city of Aleppo on April 18, 2015. Aleppo has been devastated by fighting since rebel fighters seized its eastern half in 2012, setting up a front line that carves through its historic heart. AFP PHOTO / ZEIN AL-RIFAI        (Photo credit should read ZEIN AL-RIFAI/AFP/Getty Images)