In Jordan, a ‘Stunning’ Discovery Under Petra’s Ancient Stone

A recent excavation has unearthed 12 human skeletons and a chamber of grave offerings near Petra’s Treasury building, a UNESCO World Heritage site.

By the time Dr. Richard Bates swept his radar device over the sandstone of Petra’s ancient Treasury building, it had been more than two decades since anyone had so deeply probed the stone city’s grounds.

For nearly as long, archaeologists had been stymied by a maddeningly stubborn mystery. In 2003, they had discovered hidden tombs around the city’s ornate, famed Treasury structure, carved into Petra’s canyon walls in the first century B.C. But blocked by red tape and a lack of funding, they had never been able to fully probe the other side.

That changed earlier this year, when Dr. Bates and a team of researchers were given permission to run powerful, ground-penetrating radar within the delicate Treasury monument, known locally as Al Khazneh.

“We were quite shocked that they did give us permission to go in and survey,” said Dr. Bates, a geophysicist and professor at the University of St. Andrews in Scotland. “This was stunning data.”

Now, archaeologists have answers to their longstanding hunch: An excavation has revealed an untouched tomb in Petra’s famed Treasury structure, containing 12 human skeletons and a wide collection of grave offerings, discovered just opposite of the initial find from 2003.

“People think they know Petra. They recognize the Treasury,” said Dr. Pearce Paul Creasman, an archaeologist who helped lead the excavation. “But all these people walk by, and there’s so much more under our feet.”

The discovery could be key to further unraveling the mystery of Petra, which was built by the ancient Nabatean people as their capital around the fourth century B.C. Despite such significant — and lasting — footprints, little is known about the nomadic, Arabian kingdom, which was annexed to the Roman Empire in A.D. 106.

Researchers have long hoped to more deeply explore the Petra Treasury site, and zeroed in on the tomb’s location earlier this year with the use of the ground-penetrating radar. The readings were some of the clearest that Dr. Bates, the geophysicist, had seen in his career. Voids and caverns seemed to dot the landscape opposite the tombs discovered in 2003, showing evidence that other structures might exist around the Treasury.

The evidence quickly led to an excavation by a joint Jordanian and American team, including the Jordanian Department of Antiquities and the American Center of Research, a nonprofit based in Jordan and directed by Dr. Creasman, a professor at the University of Arizona.

Among the most stunning discoveries in the newly revealed tomb were 12 intact skeletal remains, and a network of walls dividing the room — a structural feature that had not been seen elsewhere in the ancient city.

Dr. Creasman believes the tomb predates the construction of the Treasury structure, and was located underground, in front of the famous pink stone building.

Also involved in the archaeological dig was a television crew from the show “Expedition Unknown,” which recently aired an episode about the excavation on the Discovery Channel.

The ornate facade of Petra’s Treasury building is no stranger to cameras. One of the Seven Wonders of the World and a UNESCO World Heritage site, the structure’s original purpose has been debated among archaeology experts, who believe it might have been a tomb, or a hiding place for a pharaoh’s riches, rumored to be squirreled in an urn at the top of the structure.

In more contemporary history, the Treasury featured in Steven Spielberg’s 1989 movie “Indiana Jones and the Last Crusade,” as the fictional resting place of the Holy Grail.

Researchers are working to more specifically date the skeletal remains, Dr. Bates said, which broadly date between 400 B.C. and A.D. 106 — “right in the thick of the Nabatean civilization years,” he said.

For Dr. Creasman, Dr. Bates and their colleagues, the discovery does less to answer Petra’s mystery than deepen it. Dr. Bates, for one, is thinking about all of the other radar signals gleaned from that recent scan, still unexplored, below ground.

“Do we shut everything back up again and wait until we’ve got enough money to investigate further?” Dr. Bates said. “There are other voids within Petra and the Treasury area that are still yet to be opened.”

Dr. Creasman is hopeful that more discoveries — and more funding — will follow.

“I am extremely optimistic,” he said, noting the efforts of both American and Jordanian researchers. “I have confidence that we will continue to do this work collaboratively. There’s much more to learn.”