mental floss presents Forbidden Knowledge: A Wickedly Smart Guide to History's Naughtiest BitsThink of anything bad, from art heists to Genghis Kahn, and it's likely to be included in this wickedly smart and humorous guide to the seedy underbelly of basically everything. The brainiac team at "mental_floss", creators of the hit magazine and last year's Condensed Knowledge, have scoured the darkest, dirtiest corners of history and the globe to gather this ultimate collection of the bad stuff you're not supposed to know and you certainly never