Sam and Remi walked two hundred yards, then set the compass again and sighted along the foot of the next hill, and the one beyond it. Sam paced the width of the flat strip.

“I assume it’s fifty,” said Remi.

“Of course.”

“What do you think the hills were?”

“From what I’ve read, they could have been anything. They used to put up buildings on top of the earlier ones.”

“Which do you prefer?” she said. “Would you rather dig down below our feet to establish that it’s paved or climb up there and dig to see if the hill is a building that was overgrown by the jungle?”

“If we’re way up there, we might be able to see for a distance,” he said.

“That’s what I think too,” she said. “It might be nice to look above the treetops, for a change.”

They left their packs, took their machetes and folding shovels, and climbed. The hill they chose was the center one on the right side. It appeared to be the highest. The hill was steep, rising to a height of about a hundred twenty-five feet, and its slopes were thick with plants and small trees, which they used as handholds.

When they reached the apex, Sam unfolded the shovel and began to dig. After about four shovelfuls, his blade hit stone. He used his machete to test a few spots nearby and the sound was the same. Remi walked a few yards to get past a thicket of saplings, growing on the top of the building. “Don’t get lost,” Sam said.

“Come here,” she said. “You’ve got to see this.”

He took the machete and shovel with him and went through the thicket to find Remi, looking out over the tops of the jungle trees. From here, the canopy looked solid, but there were a few places where it was sparse. She pointed down at the level area they had left. “It’s like a wide road. It starts here and runs between the hills in a straight line. But it runs only a few hundred yards.”

“And over there,” Sam said, “another flat strip comes in at an angle and meets it.”

“There’s another over there,” said Remi. “Five—no, six—strips, coming in from six directions to meet at one spot.”

“It looks like an asterisk with a high wall circling the center,” Sam said.

“You could fly over this area a hundred times and not really see it,” Remi said. “The trees make everything seem natural. The shapes are rounded off, but I’ll bet this hill we’re standing on is a pyramid.”

“It’s something big anyway,” Sam said. “Well, I guess we know where we have to go.”

“Of course,” she said. “The place where the roads meet.”

When Sam and Remi reached the bottom of the steep hill, Remi said, “This is creepy.”

“What’s creepy?”