The Great Wall of China is one of the most legendary structures in history, but by 1644, it faced its greatest challenge yet. Built over centuries as a defense against northern invaders, the Wall reached its final and most formidable form under the Ming Dynasty—only to be undone by political betrayal. In this episode of History Deep Dive, we uncover the fascinating story behind the Wall’s construction, the human cost of its creation, and why, despite its grandeur, it ultimately failed to protect China. We also explore the myths, controversies, and lasting legacy of this monumental achievement.