Introduction to 3D light show: Laomendong’s light show is currently the world’s largest regularly operated 3D architectural projection show project. The 3D main videos are mainly divided into Countdown, Ode to the City Wall, Misty Rain in Qinhuai, Chengnan Memory, and Mendong New Colors. In each chapter, the historical accumulation, protection and revitalization of the old city south are demonstrated through four-season atmosphere projection, interactive photography on the smiling face wall, parent-child interactive games of knock-knock music, interactive 3D spinning bicycles and other entertainment methods and light and shadow changes.