Secret tomb found under 'Indiana Jones' filming location in Petra

Josh Gates, from left, Dr. Pearce Paul Creasman, Dr. Fares Braizat and Fadi Balawi look into the newly discovered tomb at Petra. (Discovery’s Expedition Unknown via CNN Newsource)

At the heart of the ancient city of Petra, Jordan, carved into pink sandstone cliffs, lies an elaborate monument known as the Khaznah, or the Treasury.

And buried beneath that edifice, archeologists recently discovered, is a tomb with at least 12 human skeletons and artifacts that are estimated to be at least 2,000 years old.

Archeologists led by Dr. Pearce Paul Creasman, executive director of the American Center of Research, unearthed the ancient tomb. The expedition was studying the Treasury after years of speculation that two tombs found below the left side of the monument in 2003 weren't the only secret underground chambers. But that theory had not been confirmed — until now.

Creasman and his team performed ground-penetrating radar — a remote sensing technique that uses radar pulses to detect underground objects — earlier this year to see whether the physical features on the left, where the original tombs were found, matched those on the right. The detections revealed strong similarities among the two sides, and it was the proof they needed to receive permission from the Jordanian government to dig beneath the Treasury.

At this point, Creasman contacted Josh Gates, host of Discovery Channel's "Expedition Unknown." "I think we've got something," Creasman said he told the explorer over the phone.

With a film crew, the team excavated the newly uncovered tomb in August. But the real surprise was what lay within the tomb. While many tombs uncovered within Petra are found empty or disturbed, the chamber was filled with complete skeletal remains and grave goods made from bronze, iron and ceramic. The intact burial found beneath the Treasury provides rare insight into the lives of the Nabataeans, ancient Arabian nomads whose desert kingdom thrived during fourth century BC to AD 106, Creasman said.

"This is a hugely rare discovery — in the two centuries that Petra has been investigated by archeologists, nothing like this has been found before," Gates said. "Even in front of one of the most famous buildings in the world … there are still huge discoveries to be made."

The significant finding may be the largest collection of human remains found in one place within Petra, according to researchers, and it was featured Wednesday on the season premiere of "Expedition Unknown." (Discovery Channel is owned by CNN's parent company, Warner Bros. Discovery.)

Exploring Petra, a world wonder

Petra was voted as one of the New Seven Wonders of the World in the 2000s for its unique architecture and the many mysteries that still surround the city. While experts have debated the Treasury's purpose for centuries, the most popular theory is that the monument serves as a mausoleum, although no skeletal remains have been found within the building itself, Gates said.

The Treasury receives hundreds of thousands of tourists a year, and it has also been featured in several movies, most prominently as the site of the Holy Grail in the 1989 film "Indiana Jones and the Last Crusade."

Among the artifacts were several vessels, with one skeleton found clutching a ceramic chalice that resembled the shape of the Holy Grail. "It really was this awesome moment of history imitating art," Gates said.

The artifacts are extremely well-preserved, Creasman said. However, the human remains, while intact, are in more delicate shape than expected. Their condition may be a result of the humidity and seasonal floods in Petra as well as the porous sandstone surrounding the tomb that has entrapped moisture, he said. Some of the skeletons were found with mould.

Only a handful of tombs uncovered in Petra in the past several decades have been found with untouched burials, Creasman said. Grave disturbances were most likely due to travellers looking for shade and protection in the desert, he added.

The two tombs uncovered beneath the left side of the Treasury two decades ago by archeologists from the Jordan Department of Antiquities had partial skeletal remains, but the data was not published, so it's unclear how many individuals were found, Creasman said.

"We were hopeful to find anything that might tell us more about the ancient people and place — human remains can be a really valuable tool in that regard," Creasman said. "The burials in this tomb are articulated, so the bones haven't been rummaged around and moved, so that's exceedingly rare."

Rare insight into the ancient Nabataeans

One mystery that remains surrounding the Nabataeans are their burial practices. In literature, Nabataean society is often described as being more egalitarian, with the king more integrated with lower classes than leaders of other civilizations, Creasman said. So far, out of the Nabataean tombs found, there does not seem to be a huge difference between royal and regular burials, so it's difficult to say whether the recently discovered tombs below the Treasury were designed for royalty.

The researchers also suspect that many of the textiles and jewelry that are usually found in Nabataean burials, such as cloth wrappings and necklaces and other beads adorning the bodies, were lost due to the humidity and floodwaters seeping into the tomb, Gates said.

As the researchers continue to study the skeletons, Creasman said they are hopeful more details will come to light about who the people were in life. Researchers would like to date the skeletons and artifacts as well as use extracted DNA to determine whether the dozen skeletons are related. Other analyses may be able to help assess their diets and unravel whether they had physical jobs, Creasman said.

"They must be hugely important people, because where they're buried is such prime real estate; it really is the main entrance to the city," Gates said. "I think learning who they are is really going to help unlock part of the story of the Treasury."