The world's most remarkable date palm trees might not exist if Sarah Sallonhadn't gotten sick while working as a doctor in India in 1986. Antibiotics didn't help. What cured here, she thinks, were some traditional herbal remedies.

"It was just amazing. It was so incredible," she says. "And then I got very interested. There's nothing like a doctor cured of their problem to get them interested in something."

When she moved back home to Israel, to her job at the Hadassah Medical Center in Jerusalem, she went looking for medicinal plants there. And she found lots of them. But she also heard about ancient medicinal plants that had disappeared.

"They're just historical ghosts," she says. "Like the famous date plantations along the Dead Sea, 2,000 years ago — described by Pliny; described by Josephus, the first-century historian. They're not there anymore. They just vanished!"

Sallon realized, though, that seeds from those trees still existed. They'd been recovered from archaeological sites. So she went to the archaeologists and proposed planting some of those seeds, to see if they'd grow again. It didn't go well at first. "They thought I was mad!" she says. "They didn't think that this was even conceivable."