The Underground Great Wall of China is a classified network of tunnels located in northern China, reportedly extending over 3,000 miles (5,000 km). This subterranean system is believed to serve as a strategic infrastructure for storing and transporting intercontinental ballistic missiles (ICBMs). The exact locations and operational details of these tunnels remain highly classified, with only limited public information available through military analysis and satellite imagery.
The network represents a significant component of China's nuclear deterrent strategy and military infrastructure development.