A riveting investigation of the jagged fault line between the Christian and Muslim worlds The tenth parallel the line of latitude seven hundred miles north of the equator is a geographical and ideological front line where Christianity and Islam collide. More than half of the world's 1.3 billion Muslims live along the tenth parallel; so do sixty percent of the world's 2 billion Christians. Here, in the buzzing megacities and swarming jungles of Africa...