How Japan Built the Impossible 400-Km Great Wall Against the Pacific

Discover the incredible engineering behind Japan’s massive 400-km coastal defense system, built to protect vulnerable communities along the Pacific coast from future tsunamis. In this documentary, we break down how engineers transformed lessons from the 2011 Tōhoku disaster into an enormous network of seawalls, reinforced foundations, sheet piles, embankments, drainage systems, concrete panels, tetrapods, floodgates, and monitoring technology. You’ll see not only how the wall was constructed, but why each hidden layer matters—and what could happen if even one part of the system fails. From unstable marine clay and underwater foundations to enormous concrete defenses facing the Pacific, this is the story of how Japan attempted one of the most ambitious coastal engineering projects ever built. If you enjoy megaprojects, extreme engineering, construction documentaries, and the hidden systems that keep modern civilization running, subscribe for more.