Curiosity is a good quality, but what about when it is prompted by violence? Such is often the case with ethnic and religious divisions. It would be nice if people were intrinsically interested in the difference between Catholics and Protestants or Hutus and Tutsis, but most aren’t. It sometimes take a tragedy to make people curious. Sadly, that’s the case for the divide between Sunni Muslims and Shia Muslims. The cycle of violence between them has been going on for more than a thousand years. What caused the bitter divide?