Whether evil, disturbed, or just plain mental, our society seems to have both a repulsion and fascination with the lives and minds of evil serial killers. Who are these serial killers and what motivates them to take the life of another human being? We really don’t know. But what we do know is that as humans, we are capable of some gruesome things. Take these torture devices which are meant to inflict the most pain possible. What sort of mind comes up with such terrible devices for the specific reason of torture? Serial killers in desguise maybe? Who knows. These are 25 of the most evil serial killers of the 20th Century.