Stunning secrets beneath the sandstone

A photo provided by Discovery's Expedition Unknown shows from left: the archaeologist Matthew Vincent, the television host Josh Gates, and a professor, Pearce Paul Creasman, digging in front of the Treasury building in Petra, an archaeological site in Jordan. (Discovery's Expedition Unknown via The New York Times)

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.