["Real Estate Economics, EarlyView. ", "\nAbstract\nThis study explores the long‐term economic effects of a unique form of historical architectural heritage—the city wall—on modern urban spatial structure. Using a Spatial Regression Discontinuity Design, the research compares housing prices on both sides of the Nanjing city wall, one of China's largest and best‐preserved urban fortifications. Results show a significant and consistent price premium for properties just inside the walls. Further analysis indicates that this premium is not solely due to the wall's heritage value, nor is it caused by a simple barrier effect or agglomeration dynamics on either side of the boundary. Instead, it stems from deep‐rooted path dependence within the city: early investments in the internal road network and the build‐up of local amenities, which together maintained a persistent urban structure and produced lasting capitalization effects within the wall.\n"]