It was the last hour of the last day of a long, frustrating dig, and Calliope Limneos-Papakosta was ready to go home. For 14 years the Greek archaeologist had been scouring Shallalat Gardens, a public park in the heart of Alexandria, Egypt, for traces of Alexander the Great, the ancient conqueror-turned-pharaoh who gave the city his name. Now it was time to leave—empty-handed.

Then a bit of soil shifted in the pit and Papakosta’s assistants called her over to inspect a piece of white marble poking out of the dirt. She had been disappointed in the dig, but when Papakosta saw the flash of white stone, she felt a surge of hope.

“I was praying,” she says. “I hoped that it was