Even before the arrival of the Taliban government, Afghanistan was a troubled land. One of the key reasons is its location in south-central Asia. Afghanistan lies at the crossroads of two important trade routes—one between Europe and China and one between India and central Asia. Over the past two thousand years, Afghanistan has been invaded many times by nations eager to control and profit from those routes. As one historian notes, " Afghanistan is a land on everyone's way to someplace else."

Hard to Hold

But as desperate as other nations were to control the region that is now Afghanistan, they were not able to hang on to it. Over the centuries many strong foreign armies invaded the region, only to lose it. Alexander the Great, the world's most successful invader, marched his armies into the country...