March 15, 1942

Wilford Igoe Jr. wrapped his fingers around the pumpkin-shaped rock, moved it a half inch to the left, then waited to die.

He held his breath, listening for further grinding sounds, for the sound of settling rocks — the sounds of certain death.

No sounds came. He let out a long sigh of relieved tension.

“Just a little more, Will,” said his friend Samuel, who stood behind him in the cramped cave, watching for any signs of settling.

Will could only grunt in response. The light from Samuel’s mining helmet jittered from side to side, up and down, bouncing all over the rough gray rock that filled Will’s hands. Will’s own helmet lay behind him and to the right — he’d had to take it off to squeeze into the narrow crawl space among the cluster of ancient boulders.

The headlamps’ illumination was the first light this pitch-black place had known in decades, possibly centuries. Sunlight had never graced the interior of the cave, not this far into the zone of perpetual da