Scientists Detect "Anomaly" Underground Near Great Pyramid

The mysteries of the pyramids just got deeper.

Subterranean Stash

The pyramids at Giza continue to yield ancient secrets. But this time, they come not from those towering wonders up above, but what's being described as an "anomaly" interred in the desert sands below.

Using ground penetrating radar in combination with a technique known as electrical resistivity tomography (ERT), a team of researchers from Egypt and Japan has discovered two underground structures located below a cemetery on the west side of the Great Pyramid. Something — and it's not quite clear what — is buried even below those those forbidding pyramidal tombs.

As detailed in a new study published in the journal Archaeological Prospection, the structures appear to be stacked atop one another. The shallowest is L-shaped and only around six feet underground, and measures 33 feet by 49 feet. The lower structure is a tad smaller with an area of 33 feet by 33 feet, but is considerably deeper, reaching up to — and there's that number again — 33 feet below the surface.

Dig-Free

The site of the discovery, the Western Cemetery, has long fascinated archaeologists. It's tightly dotted with rectangular mud brick and limestone tombs called mastabas. One area of the cemetery, however, is conspicuously flat and empty, which has led experts to wonder if that patch's barren surface belies underground secrets.

This is where ground penetrating radar and ERT came to fruition. The techniques, both staples of modern archaeology, allow scientists to see beneath the surface without disturbing the archaeological site.

The former technique sends pulses of radio waves into the ground, measuring how they return to reveal the densities and compositions of materials they encountered. A similar principle is applied with ERT, using the resistance of electrical currents to determine those same properties.

Pyramid Scheme

Those ground surveys veritably exhumed our curious structures, which appeared as an "anomaly" due to their sharply different densities compared to the surrounding earth. Their distinct shapes mean they're almost certainly human-made, the researchers said.

Moreover, the shallow structure appears to be packed with homogenous sand, suggesting it was deliberately backfilled after construction, perhaps serving as an entrance to the deeper structure. That deeper structure shows up as a "highly resistive anomaly," meaning it could be sand, or even more tantalizingly, a void indicative of an empty, man-made chamber.

"We believe that the continuity of the shallow structure and the deep large structure is important," they wrote in the study. For now, they can't precisely determine the materials causing the anomaly, but future ground surveys could change that.

More on: Archeologists Say They've Found Ancient Underground "Pathways for the Dead"