The cave meandered, going slightly left, then right, but always down. Sometimes the ceiling was high enough to allow them to walk upright. For some stretches, the cave was only about four feet high, and they had to crouch. Schroeder was glad to see that there was only one tunnel, with no branches that would have required a decision and increased the chances of becoming hopelessly lost.

After they had been walking for about an hour, the cave broke open to a larger space. They had no idea how big it was until they started to explore it.

As their flashlight beams bounced off the moisture that cast a sheen on the high ceilings and far walls, it became apparent that the cavern was as big as the lobby of a grand hotel. The floor was almost flat. At the far end, opposite where they had come in, was the only other opening, which loomed as large as a garage door.

They walked around the perimeter of the chamber, sipping from their water bottles, marveling at the size and shape of the space. Schroeder had been examining it with an eye toward setting up ambush, and had decided, with its nooks and wall crannies, that it would make an ideal killing field. Karla had wandered over to the other entrance, where she swept the interior with her light, then stepped inside.

“Uncle Karl,” she called out, her voice echoing.

He strode over to where she knelt on the cavern floor. Illuminated in the bull's-eye of light from her flashlight was a brownish mass of vegetation.

“What is it?” Schroeder asked.

She didn't answer right away. After a moment, she said, “It looks like elephant scat.”

Schroeder roared with laughter. “Do you think the circus passed this way?”

She stood up and touched it with the toe of her boot. A musky, grassy smell arose from the mound. “I think I need to sit down,” she said.

They found a wall outcropping to sit on and refreshed themselves from their water bottles. Karla told Schroeder about the baby mammoth that had been discovered not far from the cave entrance. “I couldn't figure out how it could be so well preserved,” she said. “No one has ever found a specimen like that. It seemed to have died only days or weeks ago.”

“Are you suggesting that there are woolly mammoths living in these caves?”

“No, of course not,” she said with a laugh. “That would be impossible. Maybe they once did, though, and the scat is very old. Let me tell you a story. In 1918, a Russian hunter was traveling through the taiga, the great Siberian forest, when he saw huge tracks in the snow. For days, he followed the creatures that made them. They left behind piles of dung and broken tree branches. He described seeing two huge elephants with chestnut hair and massive tusks.”

“An apocryphal hunter's tale, with no evidence, meant to impress?”