The subconscious or the unconscious is often perceived in dreams as a cave or place underground. We usually need to explore the unconscious before embarking on our own spiritual journey. To be on the underground or subway usually signifies the journeys we are prepared (or forced) to take towards understanding who we are. Just as Alice dreamt of falling down the rabbit hole in Alice in Wonderland, so we all have opportunities to explore our own hidden depths through dreams. We cannot usually access the unconscious in waking life, unless we practise some form of meditation or other technique, and to dream of being underground will often allow us to come to terms with the unconscious in a very easy way.