It's twice as large as an Olympic-size swimming pool and almost as long, yet for thousands of years this massive ancient monument remained hidden in plain sight at a popular tourist spot.
The huge man-made stone platform was recently discovered with the aid of Google Earth and drones, laying under the sand within the "lost city" of Petra in Jordan. The find was detailed in a study published in the Bulletin of the American Schools of Oriental Research.
It's a particularly surprising discovery seeing as Petra is such a well-surveyed archaeological sight, full of tombs and monuments carved some 2000 years ago by the Nabataeans. Yet it shows there are significant structures that remain undiscovered in the area.
Due to its monumental staircase and columns constructed on one side, it's believed the platform may have been used for ceremonial purposes. Measuring 56m by 49m, a natural plateau would have been levelled in order to build it.
"It's this very large platform that many of us (archaeologists) have walked over for years, and probably didn't even realise we were walking on it," Christopher A. Tuttle, executive director of the Council of American Overseas Research Centers, said. Tuttle, who has worked at Petra for around a decade, collaborated with Sarah Parcak from the University of Alabama at Birmingham on the study.