Alexander Rose of the Long Now Foundation posted an interesting piece about measures to communicate the whereabouts of nuclear waste, as proposed by Thomas Sebeok for the US Office of Nuclear Waste Management in 1981. In it he proposes that we create verbal and pictorial messages not only warning of the location of the hazardous material, but also asking that the message be revisited and rebroadcast in the best means possible of the current age. He proposes that we only shoot for making the message last through three generations, or about 250 years. This is definitely one of the many methods I think we should employ when seeking to preserve all aspects of our cultural heritage for the long term.