To discover secret passageways in your dream parallel to something new and/or exciting that is occurring in your waking life. It refers to a new opportunity, a new relationship, or a new attitude toward life.
If you wake up before fully exploring these passageways, then it suggest that you may not know how to take advantage of these opportunities or how to move forward with a relationship. Perhaps the newness and uncertainty of this discovery also makes you a little more cautious.
Overall, this is a positive dream.