And that 10% is concentrated mainly in places like Iran, Iraq, but they are spread throughout the Muslim world or the world in general. Now, the word Sunni comes from the word Sunnah, which is referring to examples of Muhammad. The word Shia comes from Shiatu Ali, which means followers of Ali or party of Ali. And we'll talk more about Ali in a little bit. But the general division is over who should succeed Muhammad after his death as the leader of the Muslim community. Shias believe it should be members of Muhammad's family and especially descendants of Muhammad, while the Sunnis believe that it doesn't necessarily have to be that. But as we'll see, this division becomes stronger and stronger and stronger as there's more and more bloodshed between the two parties.