His voice echoes loudly off desolate walls as the rubble crunches under his shoes.

"Here we are during the school hours, and there is not a single student here," he says.

Later, in the Syrian cave, the teacher steers his class away from the camera and back to schoolwork. "OK, let's recite what you learned today one more time," he calls out.

Abu Diyaa gets out of his way and then strikes up a conversation with a female teacher in the next room.

He asks her to deliver a message to the government.

"We will be victorious," she said, "and we will raise our children to be the teachers, the doctors and the engineers of tomorrow's Syria."