A derelict building is read as an old plan, institution or part of life that has been left to decay. Exploring it is seen as revisiting what was once important to see what still stands.
When this appeared in your dream, what were you feeling?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.