Oh yes, there's that religious thing...

Let’s see – Jews believe in God and believe that God will send a Messiah. Their Holy Book is the Torah and the Old Testament reflects their beliefs and prophets.

Christians originally were Jews who believed Jesus was the Messiah promised by God, but then went on to form a separate religion with the same God and the same Old Testament prophets, but with the addition of a New Testament based on the life and teachings of Jesus.

Muslims are people who practice Islam and they believe in the same God as Jews and Christians (they call him Allah, which means "The God"). They share the same Old and New Testament prophets, but add Jesus as a prophet, not the son of God. They also add another prophet, Mohammed, who came 700 years after Jesus, and his teachings are written in the Koran, their Holy Book, which is geared more to people of the desert.

In spite of all this similarity, these three religions have fought each other since their beginnings. Not only that, Christians have fought (and continue to fight) each other for centuries – Catholics vs Protestants. Muslims have also fought each other for centuries (and continue to fight) – Sunnis vs Shi’ites.

Hindu, Buddhist and other religious affiliations have also fought with Jews, Christians and Muslims. It seems the only group that doesn’t go around killing everyone are the Atheists.