In 1989 I had almost the same dream. People lived in enclosed cities, like giant pyramids. They were allowed out side occasionally to see a spectacle appear in the sky. The sky 'opened up' with a swirling light, and like your dream, 3 huge artifacts that almost looked like they were made of stone were affixed in the sky. One was a cat, the other a bird and the third was a fish. The people I was with thought it was "God", but I did not.