Macedonian-born Alexander the Great led his armies through Persia and Afghanistan around 330 B.C. While Greek rule continued for the next two centuries, civil unrest and revolts were common. And in 1273, explorer Marco Polo crossed northern Afghanistan on his voyage from Italy to China. Soon, the nation became a critical, if dangerous, stop on the "Silk Route," an ancient trade route that linked Rome and China.
As more U.S. troops enter Afghanistan, take a look at some of the struggles in the history of this ancient land, where war and economic upheaval are nothing new.