Throughout the history of the world, people have attempted to explain the unexplainable. To this end, they have employed magical beings as the source for that unexplainable event. The Greeks and Romans (along with various other cultures) believed in multiple gods. Some cultures were monotheistic.
For example, the Greeks believed that Zeus controlled the thunderbolt and when it stormed, it was his anger being unleashed. Fire was a gift stolen from the gods by Prometheus and given to mortal man. As learning progressed, the need for these gods became less and less. People learned that lightning was not the result of some omnipotent being hurling charges of electricity at his enemies from atop a mountain. People learned that fire was simply the result of energy transformation. As people learned, the need for magical beings was negated. The beliefs that were held to be true, became legend and mythology.
Another thing that was realized was that religion could be utilized to amass and control the people. The gods are angry at you. Come to the temple and pray. Sacrifice so that they may be appeased. A few people who have been trained and have special favor shall show you the way. These people utilized this inherent fear of the unknown to manipulate people to do their bidding. Many a conflict throughout the history of the world has, at its roots, been because of religious ideology.
Today, there are still many things that cannot be explained. Also, there are many religions that attempt to explain said things. Followers of these religions claim that one needs faith. Christians will claim that the earth and universe were created by God. Man was created in God's image. One just needs faith to see that.
There will always be things that cannot be explained. Our quest to find as many answers as possible, so that we can enlighten our sons and daughters should be our ultimate goal.
Eventually, the bible, koran, or whatever religious flavor of the day exists, will be replaced with something else. What makes the Christian bible any more "right" in the explanation of things, than the Greek Mythology? Absolutely nothing. It just happens to be the explanation-du-jour. Sooner or later, current religious tomes will be on bookshelves in the fiction section, as those of the past are today.
