The documents from the black metal briefcase described a series of ingenious killing devices set by the Nazis to protect their prize. There were machine guns whose triggers had been connected to trip wires.

“Just like the former East Germans used to employ in the border zone that separated them from the old West Germany before unification,” Zoe had said.

Then there were covered pits with stakes at the bottom.

“Just like the North Vietnamese,” Ridgeway had added.

Containers of napalm were rigged to incinerate those who triggered the mechanism. Those who escaped being immolated would probably the as the flames consumed the oxygen in the tunnel. In the larger chambers of the salt mine, where the formation was stable, antipersonnel mines had been buried beneath the salt.

All of these were marked clearly on the charts, along with procedures to avoid or disarm the devices.

But the presence of booby traps possibly added at the last minute nagged at Seth, as did a single handwritten notation inside the back cover of the booklet

“What does ‘Pfeil’ mean?” Ridgeway had asked Gunther.

“Arrow,” the Austrian had replied.

But they found no further reference to arrows. Seth had forgotten it until just now, as he ran down the list of things that squatted in the distant darkness, defying them to enter.

Gunther’s light seemed to grow brighter in the tunnel now, and Seth quickly realized it was because the man had walked into an area where the tunnel walls were white. The column quickened its pace, anxious to leave the uncertain stability of the rack-walled tunnel for the more reliable salt formation. Moments later, Gunther’s flashlight seemed to extinguish itself as they entered a giant chamber the size and dimensions of an auditorium.

Gunther stopped. “Switch on your lights for a moment, all of you,” he said. The gasps of awe came from Seth, Zoe, and Stratton as they looked about the vast white room.

“Salt formations are considered extremely stable,” Gunther said. “In addition to using them to store looted art and treasures, the Nazis actually moved entire factories into mines such as these, where they could continue to operate, safe from the Allied bombings. The hills around us are filled with chambers like this one.”

Morgen spoke next. “Some of them had been used by Jews and others as hiding places from the Nazis. On the other side of the valley there are mine chambers that are sealed off as graves. They contain the bodies of people executed by the Nazis when they surveyed the mines for storehouses and found entire families living in them.”

He turned sadly and nodded to Gunther, who ordered them once again to extinguish their flashlights. As Seth moved forward, he noticed that there was a faint brown path in the salt, created no doubt by the scuffling of Gunther and his helpers as they cut the entrance into the Habersam mine.

They followed the path around a pile of boards, rusty metal scaffolding, and a conical pile of salt that had collapsed from the ceiling of the great salt chamber.