What does it mean to dream of walking around a huge extravagant apartment?

Your dream's meaning depends on the emotions you experienced during that dream. If you felt a yearning for this apartment or one like it, this probably was an expression of your desires. Your mind produced the image of your "dream home" for your enjoyment. On the other hand, if in the dream you believed that this was your home, then that apartment represents your life, with each room symbolizing some aspect of your Self.