Measuring at least 30 meters in length, the sensational uncovering of a cavity within the 4,500-year-old Cheops Pyramid in Giza, Egypt poses an ancient riddle for researchers.

“We don’t know what the cavity means,” said Mehdi Tayoubi of the international team investigating the phenomenon. “So we don’t want to call it a chamber.” Nonetheless, the space is striking in its size.

In an article published on Thursday by the periodical “Nature,” the researchers describe the discovery as a breakthrough in understanding the internal structure of the largest of the pyramids at Giza in Egypt.

Three teams of various institutes and universities from France and Japan have been studying the millennia-old Giza pyramid for two years by employing muon particles, a byproduct of the interaction of cosmic rays with matter. The particles function like x-rays but can penetrate stone hundreds of meters thick.

“This is definitely the discovery of the century,” archaeologist and Egyptologist, Yukinori Kawae, told National Geographic magazine.

The Giza pyramids, the last surviving wonder of the ancient world, have captivated visitors since they were built as royal burial chambers some 4,500 years ago. Experts are still divided over how they were constructed, so even relatively minor discoveries generate great interest.

Tayoubi said the team plans to work with others to come up with hypotheses about the area. “The good news is that the void is there, and it’s very big,” he said.

rf (dpa, AP)