The concept of the invisible spiritual realm is so often something which is difficult for us to grasp. If we can see, hear, and feel it we can take it on face value that it is a reality. But what about things that are unseen? Scripture speaks about Heaven, Hell, Angels and Satan which are a part of the invisible spiritual realm. Bible teacher R. C. Sproul helps us glean a better understanding on these and come to a realisation that in fact all four are realities.