Euphrates Tunnel

Listen for a moment. Somewhere beyond the palm groves, the Euphrates moves slowly through the flat land south of Baghdad. The air is warm and carries dust. Underfoot, the ground is pale and crumbly, mixed with fragments of old fired brick. This is the edge of ancient Babylon, just north of the modern city of Hillah. You are standing near the place connected to one of the strangest stories ever told about this city: a tunnel that ran beneath a river.

Before we go further, an honest word. The Euphrates Tunnel is known to us mainly through writing, not through excavation. Archaeologists have not uncovered a confirmed passage under the river here. What survives is a story, told by Greek authors who wrote about Babylon from far away. So think of this stop as a visit to an idea. It is an idea that has stayed with people for more than two thousand years, and the landscape around you helps explain why.

The main source is Diodorus Siculus, a Greek historian of the first century BCE. He wrote a large world history, and parts of his description of Babylon come from an earlier Greek writer named Ctesias. Ctesias was a physician who lived at the Persian royal court. According to Diodorus, a queen built a covered passage beneath the Euphrates. It linked royal buildings on the two banks of the river, so that people could cross without a boat or a bridge.

The method described is just as bold as the idea. In the story, the builders turned the river aside into a basin, which left the old bed dry. They dug a trench across the empty channel. They lined it with baked brick and sealed it with bitumen, the natural tar that seeps from the ground in this region. They closed it with a vault. Then they let the water return over the top. In the account, the work took only a short time.

And here is the first surprise. The queen in this story is Semiramis, and Semiramis is largely a figure of legend. Greek writers gave her a long list of great deeds, from building cities to leading armies. Some historians connect her name with a real Assyrian queen, but the Greek tales grew far beyond any one historical woman. So the tunnel belongs to a legend about a legendary ruler. That does not make it worthless. It tells us what foreigners believed Babylon could achieve.

The building materials in the story are real, though, and you can see them here. Look at the broken bricks scattered across the site. Babylonian builders fired clay into hard, square bricks, and many carry stamped inscriptions naming the king who made them. They also used bitumen as mortar and as waterproofing. If you look closely at old walls, you may notice dark, glossy traces between bricks. A Babylonian engineer had the right tools for watertight work, even if no tunnel has been found.

The river itself is part of the puzzle. In ancient times, the Euphrates flowed through Babylon and divided the city into two parts. Over the centuries, the river shifted its course to the west. Rivers on this flat plain move easily, because the soft soil gives little resistance. So the water you can see or hear today is not exactly where it ran when Babylon was at its height. Any structure beneath the old channel would now lie under dry ground, silt, or later settlement.

Now the second surprise. While no tunnel was found, archaeologists did find something that crossed the river. During the German excavations led by Robert Koldewey in the early twentieth century, the team uncovered the remains of a large bridge. Its stone and brick piers had pointed ends, shaped a little like boats, to split the current. Herodotus, another Greek historian, also wrote about a bridge across the Euphrates at Babylon. Here, at least, the written account and the ground agree.

This contrast is useful for any visitor. The bridge is supported by physical remains. The tunnel is supported only by later writing, much of it from an author with a reputation for colourful tales. Historians today generally treat the tunnel as unlikely, or at least unproven. But they take the story seriously as evidence of something else: the reputation of Babylon as a place where rulers controlled water on an enormous scale.

And that reputation was earned. Life in this region depended on canals, dykes, and careful management of the two great rivers, the Tigris and the Euphrates. Babylonian kings boasted in their inscriptions about digging canals and strengthening river walls. To a Greek reader, living in a land of small streams and rocky hills, these works must have sounded almost impossible. A tunnel under a river was perhaps simply the next step in the imagination.

Take a moment to look around at the wider site. Babylon was added to the UNESCO World Heritage List in 2019. Much of what you see is low mounds, rebuilt walls, and long views across open ground. Parts of the site were reconstructed in the twentieth century, and the newer bricks look cleaner and more even than the ancient ones. Comparing the two is one of the quiet pleasures of a visit here. The old bricks are softer in colour and worn at the edges.

The sounds here are simple. Wind moves through the date palms. Birds call from the reeds along the water. On some days you may hear a vehicle on a distant road, or voices from a nearby village. In the late afternoon, the light turns gold and the shadows of the mounds grow long. It is easy, in that light, to picture the river full of boats and the far bank lined with walls.

So what do we take away from the Euphrates Tunnel? Perhaps this: a place can be remembered for things that may never have existed. The story survived because Babylon was large, rich, and skilled at working with water. Travellers carried its legends west, and each retelling made the city a little more marvellous. The truth under your feet is quieter, but it is real. Brick, bitumen, a wandering river, and the remains of a bridge.

Before you move on, turn toward the direction of the water. Look at the flat line where earth meets sky, and the green strip of palms that marks the river. Somewhere under that soil lies the old channel of the Euphrates. Whatever the ancient builders did or did not dig there, the river is still moving, slowly, as it always has. Listen to it for a moment longer... and then walk on through the city it shaped.