Millions logged on to Internet conspiracy sites alarmed that a 5,126-year Mayan cycle concluding on December 23, 2012, would mark the end of the world as we know it. The Dresden Codex, several pages of which are shown here, contains astronomical and astrological tables used to calculate this cycle. This codex is one of only three Mayan codices that survived out of an estimated five thousand; the rest were destroyed by Spanish religious authorities in the sixteenth century.