Step into one of China’s most mysterious underground worlds at the 816 Project in Chongqing 👀. Once a top-secret nuclear base hidden inside a mountain, this colossal site was carved by over 60,000 workers during the Cold War. Covering 104,000 square meters with tunnels, shafts, and caverns towering up to 80 meters high, it’s an engineering marvel often called the “Underground Great Wall."

Today, this massive cave network is open to curious travelers, offering a rare glimpse of history mixed with awe-inspiring exploration. Wander through dark passageways, see remnants of the 1960s construction era, and discover stories of resilience and mystery. Book your ticket now for a once-in-a-lifetime journey deep into the mountain ⛰️✨.