Introduction to the preface hall: The preface hall is the first part that guides the audience from modern life to ancient China. The ground is paved with stones of different colors according to the tree ring pattern. The annual rings radiate outward from the center, symbolizing the transition from modern life to ancient China. Enter ancient times. There are three exhibition items in the preface hall, namely the Taosi Ancient Observatory, the Bronze Reliefs of Ancient Scientists and Ancient Chinese Scientific and Technological Achievements.