He crawled over, picked up the light and pointed it at Karla, who was peering from the fissure. The opening was about six feet above the floor. She looked bewildered. One second, Schroeder had been there, leading the way. The next, he had dropped out of sight, the flashlight had gone flying, and she had heard a thud.

“I'm all right,” he said. “Be careful, there's a drop.”

She eased out of the hole and picked her way down the slope. Schroeder tried to stand. The fall had aggravated his injured ankle even more, and shards of pain shot up his leg when he put weight on his foot. He leaned on Karla's shoulder.

“Where are we?” she said.

Schroeder explored their surroundings with the flashlight. The tunnel was around thirty feet wide and thirty feet high. A section of the wall collapsed to uncover the hole. The ceiling was vaulted, and, unlike the cave they had come through, the floor was as level as a pancake.

“This isn't a cave,” Schroeder said. “It's man-made.” He aimed the light at the opposite wall. “Well, it seems we have company.”

Life-size figures of men and women adorned the wall. They were painted in profile, as they marched along in a procession, carrying flowers, jugs and baskets of food and herding sheep, cows and goats with the aid of large, wolflike dogs.

The women wore long, diaphanous white dresses and sandals.

The men were dressed in kilts and loose, short-sleeved shirts. Trees and other greenery made a backdrop for the parade.

The people had medium complexions, high cheekbones and raven hair worn in a bun by the females, cut short for the men. Their facial expressions were neither solemn nor happy, but somewhere in between; they could have been out for a Sunday stroll. The colors were brilliant, as if the paint had only been applied the day before.

The murals covered both walls. No figure was repeated. Most were young, in their teens and twenties, but there was a scattering of children and old people, including gray-haired men who wore ornate headgear and could have been priests.

“It looks like a religious procession,” Karla said. “They're carrying gifts for a god or a leader.”

Schroeder leaned on Karla's shoulder as he limped beside her. As they continued through the tunnel, the figures began to number in the hundreds.

“It's good to have company, in any case,” Schroeder said. “Maybe our new friends here will show us the way out.”

“They're definitely headed somewhere. Look!”

The mural had changed in nature. There were new animals in the mural—large, lumbering creatures that resembled elephants except for the shaggy, grayish brown fur covering their bodies. Flowers had been twined into their fur. The animals had high-peaked heads, and trunks that were relatively stubby. Some had tusks, almost as long as their bodies, that curved like the runners on an old-fashioned sleigh. Men rode on the animals like Indian mahouts.

“Impossible,” Schroeder said.