Palmyra occupied a position in the Syrian desert that geography had made irreplaceable and that commerce had made extraordinarily wealthy. An oasis city sitting at the crossing of the major caravan routes between the Mediterranean coast and Mesopotamia — between the Roman west and the Parthian and Sassanid east — it controlled the tolls and services that long-distance trade required and accumulated wealth that its extraordinary ruins still convey despite two millennia of decay and, most recently, deliberate destruction by forces who understood, in their way, the symbolic weight of what they were attacking.