To address it, the Department of Energy convened a conclave of scientists, linguists, anthropologists and sci-fi thinkers to develop an elaborate system intended to shout "Danger!" to any human being for the next 10,000 years, regardless of what language they speak or technology they use.

To warn future visitors of radioactive danger below, the DOE is contemplating several menacing sculptures, such as this field of concrete spikes. In this rendering, an unwelcoming, angry-looking bramble of spikes warns of the radioactive waste below. Another option is to create immense "menacing earthworks": lightning-shaped blocks that radiate out of an open-centered Keep.

The waste site will be surrounded by a four-mile outer fence of dozens of 25-foot, 20-ton granite markers engraved with multi-lingual and pictographic warnings. "Egyptian hieroglyphics lasted thousands of years, but it took us years of research to decipher them," says Givens. "We want ours to be self-explanatory." That means pictures, as well as words.