This episode, a look at one of the most challenging design problems facing humanity- a warning system for nuclear waste burial sites- and a 30-year-old proposal for a system that relies not on signs or markers, but on religion.Further Reading:99% Invisible - 'Ten Thousand Years':http://99percentinvisible.org/episode/ten-thousand-years/Sebeok, Thomas - 'Communication Measures to Bridge Ten Millennia:https://www.osti.gov/scitech/servlets/purl/6705990Sandia National Labs Report (1991):http://prod.sandia.gov/techlib/access-control.cgi/1992/921382.pdf