DNA, climate,” she murmured softly to herself. “Why would they try to—”
“Think about it,” Ethan said with a brief smile. “There may be one in every ancient city.”
Rachel gasped, her eyes flying wide.
“My God,” she said. “They left it here on purpose. It’s a Rosetta stone.”
What the hell’s a Rosetta stone?” Lieutenant Ash asked, dumbfounded.
Lucy gestured to the remains.
“It’s a stone tablet that recorded a decree issued in Memphis by King Ptolemy over two thousand years ago. The decree was in three texts: Egyptian demotic script, ancient Greek, and Egyptian hieroglyphics, and allowed archaeologists to decipher hieroglyphics for the first time. Don’t you see? They must have left behind one of these skeletons at the site of every early civilization they encountered; that’s why Sheviz found fragmentary remains in different countries.”
Jerah Ash shrugged.
“Why bother?”
“Because it was the best way for them to leave us a message,” Lucy gasped, turning a full circle on her feet and holding her hands to her head. “My God, I can’t believe I didn’t realize it before.”
“You think that’s what really happened?” Ethan asked.
“Of course,” Lucy replied. “For years we’ve wondered, if they visited us in the past, why they hadn’t left markers or evidence of their presence. We know the ancients expended enormous effort, materials, and even lives on building temples and pyramids when the time would have been better spent building fortifications instead, so whatever the reason it must have been important. So why would such visitors just leave our ancestors to build ambiguous megastructures, maintain oral traditions, or carve figurines that could be interpreted in any number of ways? But we’ve been looking at the problem the wrong way round, thinking in terms of our own technology, not theirs.”
Rachel frowned.
“You think that the answer is in the burials?”
“Not the burials,” Lucy said, “but the bones, the mitochondrial DNA. That’s why the blood could be so important. O-negative blood could have had its origins in these beings. If so, the fact that it remains today means that it could be traced via people with O-negative blood using mitochondrial DNA that’s been passed down the feminine line from seven thousand years ago.”
Ethan thought for a moment.
“Could they actually do that? Leave a message in the remains?”
Lucy nodded enthusiastically.
“It would be like a message in a bottle,” she said. “The bottles are living cells and the message is encoded in mitochondrial DNA. Viruses are designed to infect organisms on Earth and upload their DNA into the genomes of those organisms, so there is a well-understood pathway for getting information into DNA. Our own genomes have got huge amounts of this junk that has climbed onboard from viruses over evolutionary history. Now there could be a message encoded in it, maybe in a string of nucleotide bases.”
Ethan caught on to her train of thought.
“We wouldn’t be able to decipher the message until we’d reached a certain technological standard.”
“Exactly,” Lucy agreed. “And the climate change since these beings were on our planet has hidden the evidence from view.”
“How?” Rachel asked.
“Virtually all of the megastructures that appeared during the Bronze and Copper Ages can be considered as cargo cults,” Lucy said, “but we can’t see all of them anymore because so many of them are underwater.”
“Underwater?” Rachel repeated.
Lucy nodded.
“All of the world’s religions have their global flood myth, like Noah in the Bible. About a decade ago divers off the coast of Japan found an enormous city complete with its own pyramid. It’s called the Yonaguni Formation, and is around eight to ten thousand years old. Sea levels were much lower after the Younger Dryas when these cities were first flourishing, and like today people built on rivers, floodplains, and coastal estuaries. When the planet warmed, the glaciers melted, and sea levels rose and swallowed entire cities in a matter of years, burying them forever. Many of mankind’s earliest megastructures are to be found not on land but underwater.”
“How sure can you be?” Ethan asked.
“Yonaguni isn’t the only one,” Lucy said. “There are others: Dwarka, off the coast of India, and Poompuhar, in the Bay of Bengal, a submerged city that may be Kumari Kandam, where local fishermen are often forced to dive to free their nets caught on underwater temples with columns, pyramidal pagodas, and buildings with doorways.”
“So there may be other humanoid remains like the one you found, marking the locations of ancient settlements,” Lieutenant Ash said, trying to keep up.
“Exactly,” Lucy said. “It all fits, and even explains why in the ancient past it wasn’t