It’s 1851, and French Egyptologist Auguste Mariette strides up to an imposing tower of boulders, ready to blast them with explosives. When the dust clears from the detonation, though, an extraordinary subterranean labyrinth from more than 3,000 years ago finally reveals itself. And the mysterious stone boxes that Mariette finds within the structure are astonishing – even if they present a seemingly unsolvable puzzle.

Specifically, Mariette had unearthed an ancient burial ground known as the Serapeum of Saqqara. This landmark lies about 15 miles south of Giza, which plays host to Egypt’s best-known pyramid site. And the structure of the underground burial chamber is basically that of a tunnel bored into the rock of a mountain. Positioned off that passageway, meanwhile, are a series of chambers or alcoves.