City
To see a city in your dream signifies your social environment and sense of community. If you dream of a big city, then it suggests that you need to develop closer ties and relationships. You are feeling alienated and alone. To dream that you are in a deserted city indicates that you feel rejected by those around you.
To dream of a city in ruins denotes that you are neglecting your social relationships and allowing them to deteriorate.
To dream of an underground or underwater city represents your subconscious and how, through a deeper understanding of yourself, you find commonality and shared experiences with others.
Dreaming of a city in the sky implies that you are being too idealistic. You have overly high hopes for those around you.