Petra: the Rose-Red City Carved from Stone

There is no entrance to an ancient city anywhere on earth quite like the entrance to Petra. The traveler comes from the dusty desert plateau of southern Jordan, passing through the modern visitor center and then descending into a dry riverbed valley that narrows imperceptibly, the canyon walls rising on either side, the path threading between boulders and smooth stone faces until, at some uncertain point, the passage becomes the Siq — one of the most theatrical approaches to any archaeological site in the world. For 1.2 kilometers, the traveler walks through this narrow gorge, the walls rising to 80 meters on either side, the sky reduced to a ribbon of blue overhead, the sandstone all around shifting through extraordinary gradations of color: red, amber, purple, lavender, cream, ochre. The passage twists and turns, offering nothing to prepare the mind for what is coming. And then, at the end of the last bend, the Siq opens out and the Al-Khazneh appears in the cliff face directly ahead — a facade of breathtaking scale and refinement, approximately 40 meters tall and 28 meters wide, carved entirely from rose-red sandstone, its columns and pediments and carved figures standing in pristine exactitude after two thousand years. The effect is one of the most startling in all of human experience: astonishment, incomprehension, and the overwhelming presence of a civilization so accomplished in its grasp of beauty that it chose to make its greatest monuments not by building upward into the sky but by cutting them directly into the living rock of a desert canyon.

This is Petra, the ancient capital of the Nabataean kingdom, located in the Arabah valley of what is now the Hashemite Kingdom of Jordan, approximately 240 kilometers south of the capital Amman. It is a UNESCO World Heritage Site, inscribed in 1985, and in 2007, in a worldwide vote organized by a Swiss foundation, it was named one of the New Seven Wonders of the World. The British poet John William Burgon, who won the Newdigate Prize at Oxford in 1845 with a poem about Petra, gave it the description that has followed it ever since: "a rose-red city half as old as Time." The description is poetically imprecise — Petra is not a single rose-red color but a thousand variations — but it captured something essential about the place, and the phrase has clung to it for nearly two centuries.

The Nabataeans: Masters of the Desert

Before there was the spectacular architecture, before the carved facades and the cut stone channels and the elaborate tombs, there was the Nabataean people — one of the most remarkable civilizations of the ancient world, and one of the least well understood. The Nabataeans appear in ancient sources as a nomadic Arab people living in the region of the Negev, the Sinai, and the northwestern Arabian Peninsula. The earliest historical references to them come from the late fourth century BCE, when accounts from the period of the successors of Alexander the Great describe them as a fiercely independent desert people who had resisted conquest by mounting a vigorous defense of their rocky plateau stronghold. They were, initially, a nomadic people whose wealth came from controlling the movement of goods across the vast desert spaces of the ancient Near East.

Over the following two centuries, the Nabataeans underwent a profound transformation: from nomadic traders to settled urbanists, from desert wanderers to architects and engineers of extraordinary sophistication. The mechanism of this transformation was commerce. The ancient world ran on commodities that could only be obtained from specific and distant sources: frankincense and myrrh came from the southern Arabian Peninsula, specifically from the Dhofar region of modern Oman and from parts of what is now Yemen; spices came from India; silk came from China; precious metals came from Africa and from the mines of the ancient world. All of these goods needed to move overland to reach the markets of the Mediterranean world, the great cities of Egypt, the Levant, and Greece. The routes they traveled passed through the territory the Nabataeans controlled, and the Nabataeans had the organizational capacity, the knowledge of the desert, and the military force to make themselves indispensable to these trade flows.

At the height of their power, between approximately the second century BCE and the first century CE, the Nabataeans controlled what amounted to a commercial empire that stretched from the Hejaz in the south to Syria in the north, from the Sinai in the west to the Gulf of Aqaba in the east. Petra sat at the heart of this network, a city of between 20,000 and 30,000 inhabitants at its peak — an extraordinary figure for a location in the middle of one of the harshest deserts on earth. The wealth that flowed through Petra was immense. Caravan trains carrying frankincense and myrrh, bales of spices, bales of silk, precious stones, copper, and ivory arrived and departed constantly. Petra was a city of merchants, financiers, caravan masters, and craftsmen, and its prosperity expressed itself in the extraordinary built environment that the Nabataeans created.

What made the Nabataean achievement at Petra so remarkable was not merely the scale of their architecture but the conditions under which they built it. The Arabah valley receives very little rainfall — perhaps 50 to 100 millimeters annually, most of it falling in brief, violent winter storms. For a city of tens of thousands of people to survive in such an environment required an engineering solution of exceptional ingenuity, and the Nabataeans provided one. They cut channels, pipes, and cisterns directly into the sandstone throughout the city and its surrounding landscape, capturing every drop of rainwater and every trickle from distant springs and conducting it through a network of gravity-fed channels to reservoirs and distribution points within the city. The system included sealed clay pipes, settling tanks to filter sediment, and an elaborate hierarchy of collection and storage that allowed the city to maintain water supplies even during extended droughts. This hydraulic genius was perhaps the Nabataeans' greatest single achievement — it made life in Petra not merely possible but prosperous, and it is one of the most impressive examples of ancient water engineering anywhere in the world.