This is a question I have heard before. Adam and Eve were first but I believe that God followed to create others as well after humans proved to not be perfect creatures. That's what God wanted but also realized would be impossible to do if he wanted them to have free will and make decisions for themselves. Jesus dying for our sins was God's ultimate way of trying to get people to believe in him, to show people what his love is all about. There was also a point where Earth grew so dark and grotesque that he decided to flood the entire surface and wipe it clean. The second part of your question is a little vague to me. Maybe you can reword it? What exactly are you asking about the Crucifixion of Jesus?