What's behind the latest deadly attack in northern Nigeria?

Northern herders launch a deadly attack on farmers in Plateau State, Nigeria, leaving over 140 people dead and hundreds more injured. What's behind this cycle of violence?Also we follow the stories of migrants from North Africa, across the Mediterranean Sea, to Lampedusa, an island off the Italian Coast. It's one of the deadliest known crossings in the world. Not everyone makes it across safely. And we meet the award winning Ethiopian scientist, creating drought resistant and weed resistant African grains!