Abu Bakr al-Baghdadi, the leader of the jihadist group Islamic State (IS) was arguably the world's most wanted man. The self-styled Caliphate leader had a $25m bounty on his head and was being pursued by the US and its allies for the last five years. Baghdadi - whose real name is Ibrahim Awwad Ibrahim al-Badri - was born in 1971 in the Iraqi city of Samarra. He moved to Baghdad in the early 1990s where he pursued a master's degree in Islamic studies and then a PhD. In early 2004, Baghdadi was even detained by US troops, and was taken to a detention centre, but was considered a low-level threat and was released after 10 months. Baghdadi disappeared from sight in 2014, only resurfacing in a video in April this year, as he encouraged his followers to "take revenge" after the ISIS' territorial defeat.