The resource that made a desert metropolis possible now threatens to destroy it
![[image]](thumbnails/petra.gif)
A team led by chemist Talal Akasheh maps Petra's "Obelisk Tomb," which was carved 2,100 years ago. Akasheh, shown bottom right, is discovering how this desert city of 30,000 people flourished. (Rolex Awards/Marc Latzel)
Talal Akasheh circles the base of a 30-foot-tall sandstone block, marveling at the weathered beauty of its carved columns. The local Bedouin tribes named these crumbling monuments Djin, or "spirit" blocks, believing that they harbored phantoms. Some archaeologists suggest they served as tombs; others regard them as funerary markers or abstract representations of a desert god. Whatever the truth may be, the Djin blocks towering along the outskirts of Petra are intimately connected to a precious commodity in Jordan's arid Shara Mountains: water. Indeed, the enormous stone blocks in front of Akasheh, a chemist and conservation expert at Jordan's Hashemite University, guard two of the primary conduits that supplied the 2,100-year-old city with water.
Akasheh is exploring Petra's 21-square-mile hydraulic system, which collected and conserved the region's scarce rainfall. It is no small irony that water is now destroying the Djin blocks, as well as much of Petra's most iconic architecture. Akasheh and his colleagues recently used X-ray fluorescence to trace contours within the stone of one Djin block, where evaporating rainwater has left heavy concentrations of salts. As these salts crystallize, they expand inside the stone, splitting off slabs more than a foot in length. Petra's deterioration is accelerating as the region becomes a desirable place for real-estate development, and ever-increasing numbers of tourists come to see the rock-cut buildings of the city that connected cultures from Italy to the Arabian Peninsula at the time of Christ.
Tucked into a remote inland valley where just four inches of rain fall each year, Petra is one of the ancient world's most beautiful and improbable trade emporia. It possessed few resources of its own, but bordered several important caravan routes leading from the Arabian Peninsula to the Mediterranean. And as the camel trains lumbered past with cargoes of pepper, frankincense, and other luxuries, the Nabateans--Arab pastoralists and camel breeders who knew the deserts of the region intimately--saw an opportunity. They levied hefty taxes on the caravans and became so wealthy that they were able to create a sprawling desert kingdom and embark on a building spree that peaked in Petra during first and second centuries A.D. Nabatean artists and stone cutters blended architectural ideas from Greece to Egypt, and created one of the world's great urban masterpieces--a city of some 30,000 people teeming with temples, villas, gardens, fountains, and pools. But the remote capital suffered after trade in the region shifted to shipping routes on the Red Sea and the rise of Islam fueled the growth of new cities in the region. Petra was abandoned after the seventh century A.D., and eventually the world forgot about the city and its ingenious builders.
Today, after nearly eight decades of scientific excavation, archaeologists marvel at the emerging picture of the Nabatean civilization. But as tourists flock to Petra Archaeological Park--a 102-square-mile area encompassing at least 60 major sites--the great sandstone ruins are crumbling away. "Petra looks dead," says Martha Sharp Joukowsky, a professor emerita at Brown University and a longtime excavator at the city, "but it is a living, evolving site, and it's undergoing tremendous change." As tourism encroaches on the ancient city and the monuments weather, the facades of some of its most famous buildings are literally falling to pieces.
Heather Pringle is a contributing editor at ARCHAEOLOGY.
