This is the beauty of life. People have the ability to choose whether or not religion should play a role in their daily actions. At some point in life, everyone is faced with the question of whether or not he or she believes in God. This is one question that everyone is forced to answer. The reason why is that there is a God, and the majority of people in this world know it.
People know that there is life after death.
Those who deny this simply have not given it much thought. It is sometimes easier to look at the conditions of the world and surmise that if there were a God, He would not let what's going on happen. This is a very intelligent assumption. God did not invent the gun, the bomb, or any other devices used for mass destruction. Humans did, and humans have decided to use those things to hurt others.