What strikes you first about Balkh are the fortifications. Brick and mud walls, at least thirty feet high, completely enclose the town. They remain in remarkably good condition after centuries of exposure and warfare. Climb them -- visitors do -- and the view opens in every direction: green fields stretching toward the mountains to the south, the low buildings of the modern town below, and the flat agricultural plain running north toward Mazar-e Sharif. The walls slope on the outside but drop vertically on the inside, creating the disorienting impression that they are taller than they actually are. Turrets in varying states of decay punctuate the perimeter, each one revealing layers of construction technique from different eras. At the north end, a large mound marks the site of the old fortress, the highest point in a town that has been built, destroyed, and rebuilt on top of itself for three thousand years.

Balkh's ancient name was Bactra, and it gave its name to Bactria, the region that became one of the most improbable outposts of Greek civilization. After Alexander's conquests in the fourth century BCE, his successors established a Greco-Bactrian kingdom here that minted coins bearing Greek gods and spoke a dialect of Greek thousands of miles from Athens. The kingdom lasted more than a century, a cultural hybrid where Hellenistic art met Central Asian steppe traditions. The Seleucid Empire besieged Bactra from 208 to 206 BCE without success, and the city's stubborn resistance became a lesson that even the great empires of antiquity could not always take what they wanted. Balkh would be conquered and destroyed many times after that, but the pattern held: the city always came back.

Two of the medieval world's most celebrated travelers visited Balkh and left their impressions. Marco Polo arrived in the thirteenth century, after the Mongol devastation, and described a city of former grandeur reduced but not extinguished. Ibn Battuta came in the fourteenth century and found a city "in ruins and uninhabited" yet still recognizable as something that had once been magnificent. That these two men, who between them saw more of the medieval world than almost anyone alive, both detoured to Balkh says something about the city's lingering reputation. Even in ruin, it pulled travelers off their routes. Even silent, it had stories worth hearing.

Modern Balkh is a small town, reached from Mazar-e Sharif by a twenty-minute shared taxi ride costing about twenty afghani. The road passes through a fort littered with destroyed tanks and armored personnel carriers, relics of more recent conflicts. Inside the walls, life continues at a modest pace. The town center holds a park shaded by trees, where children play soccer and volleyball. At one end stand the ruins of a tiled mosque; at the other, the gate of a madrassa whose construction techniques are visible in its partially exposed walls. Small shops ring the park. Dari is the dominant language, though Pashto, Tajik, Uzbek, and Russian are all spoken in this border region. English schools operate here, and travelers report being invited into the homes of English teachers eager to practice conversation. The students, they say, are shyer about trying their skills.

Balkh earned the title "Mother of Cities" across multiple traditions, a recognition of its antiquity and centrality to the region's identity. That such a city could be emptied not by armies but by illness -- the epidemic that drove the population to Mazar-e Sharif in the mid-nineteenth century -- carries its own bitter irony. The city that survived Alexander, Genghis Khan, and Tamerlane was undone by something invisible. Today, Balkh is not abandoned but diminished, a living town wrapped in the shell of something far greater. The walls endure. The ruins teach. And the fields that surround the town still produce crops from the same soil that fed Bactrian Greeks, Mongol armies, and Timurid courts. History here is not a subject to study. It is the ground beneath your feet.