For over two-thousand years, a massive, mysterious structure has been hiding in plain sight at the ancient desert city of Petra.
Two archaeologists, who recently published their findings in the American Schools of Oriental Research, used Google Earth satellite images and drone photography to identify the outline of an enormous monument buried beneath sand and time at the UNESCO World Heritage site in Jordan.
"I'm sure that over the course of two centuries of research [in Petra], someone had to know [this site] was there, but it's never been systematically studied or written up," co-author Christopher Tuttle, executive director of the Council of American Overseas Research Centers, told National Geographic. "I've worked in Petra for 20 years, and I knew that something was there, but it's certainly legitimate to call this a discovery."
According to the researchers, Petra represents one of the most well-studied and surveyed archaeological sites in the world. Thousands of structures within the city center and surrounding geography have been catalogued since the site was opened to the western world in 1812 by Swiss explorer Johann Ludwig Burckhardt. Yet, somehow, the 184 by 161-foot-long platform remained hidden from archaeologists for centuries.
Tuttle and his colleague, Sarah Parcak, an archaeologist and Egyptologist at the University of Alabama, believe the gigantic monument served as a public ceremonial structure. No one has been allowed to excavate the site as of yet, but surface pottery discovered nearby was successfully dated to the mid-second century BC. During this same period, Petra became a bustling trade hub for the ancient Arab kingdom of Nabataea.
Aerial imagery also revealed the impressions of a smaller, 28-by-28-foot building that once sat atop the structure, as well as a facade of columns and a staircase that have since disappeared.
Many of Petra's most famous locations, such as The Treasury or Raqmu, were raised between the end of the first century BC and the second century AD, according to National Geographic. So the existence of a much older monument would shed new light on the city's earlier public building campaigns.
While an exciting discovery, this isn't the first time that aerial photos have been tapped to hunt for ancient archaeological sites. Parcak herself, who prefers the worthy title of "space archaeologist," helped to commandeer the innovative use of satellite imagery and crowdsourcing to explore regions of the Earth currently off-limits to researchers.
"I wish for us to discover the millions of unknown archaeological sites across the globe," she told the International Business Times earlier this year. "By building an online citizen science platform and training a 21st century army of global explorers, we'll find and protect the world's hidden heritage, which contains clues to humankind's collective resilience and creativity."
Elsewhere, a team of researchers at the University of California San Diego's Center of Interdisciplinary Science for Art, Architecture and Archaeology is attempting to uncover the long-lost tomb of Mongol emperor Genghis Khan, using UAVs and high-resolution images collected by a custom satellite. Legend has it that Khan's secret tomb is nestled somewhere in the northeastern region of modern-day Mongolia, though many explorers have failed to find it.
Thousands of online volunteers have also enlisted in the collective hunt for Khan's burial place. A massive collaborative study published last year to PLOS ONE resulted in 3.4 years of total research time, 6,000 square kilometers of landscape explored, and 2.3 million feature inputs by participants all over the world. The project's findings instigated a National Geographic expedition that was able to confirm 55 archaeological sites across the Mongolian steppe.
Amateur archaeologists can now globetrot to their hearts' content, thanks to Google Earth communities like The Megalith Portal, which contains approximately 25,000 prehistoric and ancient sites that users can traverse, catalogue, and survey. Both professionals and hobbyists seem to agree that open-access platforms are a good thing for the field of archaeology, and—at the very least—allow people to discover a newfound passion for exploration.