It’s October, folks. The season of mystery. So this week, to kick off our favorite month of the year, we’ve picked two of the most iconic unsolved cases in American history: both cases where the basic fabric of everyday life was threatened. Where the things we take for granted as safe—over the counter medicine and air travel—suddenly couldn’t be trusted. Both of these cases rocked the country to its core. And both of them remain unsolved to this day. Case 1: The Tylenol Poisonings. Case 2: D.B. Cooper.