This Bible story of sibling jealousy and murder has puzzled scholars for centuries. From Egyptian burial tombs to the mountaintops of Iran, archaeologists investigate a tale that impacts all of humanity. Both the Koran and the Old Testament offer tales of Cain and Abel, the sons of Adam and Eve. The men offered sacrifices to God, but when God favoured Abel, Cain was filled with jealousy and killed his brother. Did this event really happen?