Houchengzui Stone City Tunnel Network

under excavation

Archaeologists discovered a hidden network of six interconnected tunnels beneath the nearly 4,500-year-old Houchengzui Stone City in northern China. The tunnels, engineered with arched ceilings and consistent dimensions, plunge as deep as 20 feet below the surface and radiate outward from the city's center, threading beneath walls and gates and emerging beyond the outermost fortifications. The tunnels likely served both military and economic purposes, allowing covert transportation of materials and safe transport of goods underneath the city.