An Ancient City’s Demise Hints at a Hidden Risk of Sea-Level Rise
Sometime in the third century B.C., an earthquake struck the eastern Mediterranean. In Thonis-Heracleion, past its peak but still one of Egypt’s greatest ports, the ground began to shake, and the soil gave way. The city had been built upon low-lying islets, bits of silt and clay left behind from the Nile’s summer floods. Temples would have towered over the city, where each year, priests would form the earthly body of Osiris—the god of the afterlife and rebirth—from gold, barley grain, and river water.
In the smallest part of a second, the mud on which the city stood would have turned to liquid. The great temple to the supreme god Amun-Gereb fell into the sea.
The city did not vanish entirely that day, but without the temples, it lost its raison d’être. By the eighth century , the last of its mud islets had slipped beneath the waves as the river shifted and the sea level rose. The city passed into the realm of rumor and myth. Herodotus, the Greek historian, wrote that Helen and Paris had visited before sailing to Troy. Stelae half-buried up the Nile mentioned it. A scroll found far to the south preserved a hint of its tax records. It was an antediluvian world barely more solid in history than Atlantis.
