人们想知道，是什么使伊拉克北部的这一地区成为历史上的一条主要断层线——一次又一次地被历史性喷发所标记，这些喷发实际上改变了时间的进程——两股不可改变的力量聚集在一起，迫使一方在经历了最激烈的斗争后才做出让步。波斯军队在巴比伦附近集结。如果大流士留在这里，亚历山大就会被拉向南方，进入大流士自己选择的战场。相反，这位波斯领导人将他的军队向北推进320公里，在历史上最活跃的断层线之一的小镇高加梅拉（Gaugamela）与前进的亚历山大军队会合。

One wonders what makes this area in northern Iraq one of history's major fault lines -- places marked over and over again by historic eruptions that literally change the course of time -- places where two immutable forces come together, forcing one to give only after the greatest of struggles. The Persian army had massed near Babylon. If Darius had stayed here, Alexander would have been drawn southward into a battle site of Darius' own choosing. Instead the Persian leader pushed his troops 320 kilometers northward to meet the advancing Alexandrian army in the small town of Gaugamela, on one of the most active fault lines in history.