A nuclear waste vault in New Mexico will long outlive our society. Experts are working on elaborate ways to warn future civilizations.

"No culture has ever tried, self-consciously and scientifically, to design a symbol that would last 10,000 years and still be intelligible," said David B. Givens, an anthropologist who helped plan the nuclear-site warnings. "And even if we succeed, would the message be believed?"

Trying to communicate across 500 generations posed an unprecedented challenge of linguistics, semiotics and materials science, so the government first asked scientists, futurists and historians to envision what the far-distant future might be like.

Roger Nelson, chief scientist of the Waste Isolation Pilot Plant, considers 30,000-year-old cave drawings: "I understand those cave drawings and I don't speak Neanderthal…. He's killing a bison, 'bison — food!' I can do pictographs just as well," he said. "I can convey an absolute sense of danger."

The site would be surrounded by 48 granite or concrete markers, 32 outside the berm and 16 inside, each 25 feet high and weighing 105 tons, engraved with warnings in English, Spanish, Russian, French, Chinese, Arabic and Navajo, with room for future discoverers to add warnings in contemporary languages. Pictures would denote buried hazards and human faces of horror and revulsion.

The same symbols would be printed on metal, plastic and ceramic disks with abrasion-resistant coatings, 9 inches in diameter, that would be buried just below the surface.

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