How did Japan build one of the world’s most ambitious engineering projects—a 400 km Great Wall designed to defend entire coastal communities from devastating tsunamis? In this episode, we uncover the incredible story behind Japan’s Secret Mega Project, exploring the massive sea walls, cutting-edge engineering, the lessons learned after the 2011 Tōhoku earthquake and tsunami, and the ongoing debate over whether these colossal barriers can truly protect the nation from nature’s most powerful forces.

Discover the history, construction, cost, and impact of Japan’s giant coastal defense system, and learn why this hidden megastructure is one of the greatest engineering achievements you’ve probably never heard of. If you’re fascinated by engineering megaprojects, Japan, natural disasters, tsunami defenses, infrastructure, technology, and world his ...