After weeks of sharing cramped quarters with relatives during last year's conflict between Hamas and Israel, 39-year-old Mohammed al-Selek thought nothing of it when he heard the incoming roar of mortar shells on July 30. But when a suffocating cloud of acrid smoke filled the stairwell, his heart sank - the family's home had been hit by Israeli fire.

Moments before, he had been enjoying a rare break, relaxing with a cup of tea and cookies as he marked the end of the Muslim holy month of Ramadan. The house was filled with his children, nieces and nephews, and his father had taken the restless kids to play on the roof, where the family kept rabbits and chickens.

After the explosion, Selek and his wife ran up the five flights of stairs to the roof and found a sight he still struggles to comprehend.