Inside Secret Societies investigates the mysterious secret society known as 'The Priory of Sion' that traces its roots back to the 12th Century and is believed to protect incontrovertible, if heretical, information about the marriage of Jesus Christ.

Inside Secret Societies uncovers what lies behind the history of the overwhelming military power of the Nazis: their strong belief in ancient mysticism, the occult, and even alien contact which fueled their desire to rule as a genetically pure race.

Sworn to protect and preserve the Holy Blood of Christ, the Brotherhood of the Blood are a dark and mysterious sect. We go on a quest to shed light on a group shrouded in secrecy through the ages, revealing the extreme methods the Brotherhood used.

The Assassins were one of the mostly deadly, notorious and secretive groups in the Medieval world. But is the romance behind these brutally efficient killers true? Have their skills and tactics been copied by today's Islamic terrorists?

This episode unearths the secrets of a widespread criminal gang in the heart of Japan. They're engaged in a variety of criminal activity including extortion, prostitution and illegal gambling. It is a hard-hitting, slick-dressing network of gangs.

We delve into the world of the most notorious white supremacist group in America... the KKK. Once having over a million members, today it's just a shadow of its former self. We meet real members and look at the impact of the group has had on America.