Watch The World's Most Evil

Few men have perpetrated crimes against humanity in such a violent manner as Francisco Pizarro. In the 16th century the Spanish Conquistadors tore into the New World of South America.

King John was cruel, ruthless, greedy and violent - the first ever King to be called to account by his subjects. By the time he took the throne, he had already plotted to depose both his father and brother.

In a castle amid the mountains of 16th century Slovakia lived a Countess who bathed in the blood of her servants to retain her youth and beauty. Countess Elizabeth Bathory was one of the most powerful and feared figures in the area.

Mary Tudor stands alone as the most hated British monarch of all time. She possessed a seething hatred for those that had supported her father, Henry VIII in his rejection of the Pope and set about violently transforming the country back to Catholicism.

In a bloody six-year reign, Prince Vlad Dracula explored the delights of impalement, mass murder and repression, not only against his enemies, but his own people.

To his enemies Grigori Rasputin was the incarnation of evil. Implicated in murder, corruption and the eventual destruction of the Romanov Royal family, Rasputin was instrumental in wiping out the 300 year old dynasty and changing Russian history forever.

His ruthless unification of Russia and savage treatment of the nobility earned him the admiration of Stalin, but to the rest of Europe he was a cruel and paranoid despot who boiled, fried, hanged and drowned thousands of his subjects.

Ilse Koch was a woman of unimaginable evil whose story caused a worldwide sensation during the concentration war crimes trials at Dachau. This programme provides a much-needed biography of a truly evil product of the Third Reich.

In a society which revelled in brutal gladiatorial games and savage public executions, Caligula's behaviour caused shock and horror. In less than four years his love of sadism and sexual abuse earned him a reputation still remembered two thousand years on.

Attila The Hun and his bloodthirsty Barbarians tortured, raped and murdered all who stood in their way. In this programme we profile the man who Christians called 'The Scourge Of God'.