4 as a child I lost a bouncy ball under my bed but moments later it mysteriously reappeared. 5 the Zodiac Killer evaded capture and despite theories no one knows their true identity. 6 the Voynich Manuscript an undeciphered book with drawings of non existent plants remains a mystery. 7 the Lead Mask Mystery in Brazil two men found with lead masks and cryptic notes their deaths unexplained. 8 neither science nor medicine can explain the origins of consciousness.