A MOUND OF filth blocks the highway to a walled compound on the outskirts of al-Qutayfa, a city round 30km north of Damascus, the Syrian capital. It is silent, save for the occasional bark of two stray canines and the faint buzz of energy traces operating over the compound. Breeze-block partitions enclose an space roughly the scale of two soccer fields. For greater than a decade, Bashar al-Assad’s military turned this wasteland right into a mass grave—believed by Syria’s new rulers to be one among his largest.