There are some crimes that stay with you forever. Not because of their gruesome nature, their high body counts or their despicable perpetrators, but because, despite all the efforts of investigators, they remain unsolved. The most infamous cold cases have inspired many reenactments, from Hollywood blockbusters to copycat killers. The identity of Jack the Ripper is still a mystery and debated over today, more than a hundred years after the Whitechapel murders took place. More recently, the world still wonders what twisted individual committed the Zodiac killings and sent taunting letters containing cryptograms to the local press. And will Madeleine McCann, snatched from her bed at three years old, ever be found? Packed with crime scene photos, maps of killers’ hunting grounds and suspicious suspects, the world’s most notorious unsolved crimes are featured within these pages. So if you’re ready, let’s take a look inside the investigations that remain unexplained to this day…