Adolf Hitler seemed an unlikely leader – fuelled by anger, incapable of forming normal human relationships and unwilling to debate political issues. Such was the depth of his hatred that he would go on to become a war criminal arguably without precedent in history - his hatred would lead to the Holocaust, his desire for conquest would leave much of Europe in ruins, and his determination caused the death of 60 million people. Yet he was once loved by many. In the first of a three part series, Laurence Rees looks at how this was possible, with testimonies from those who lived during the era, archive film and specially shot documentary footage.