How Japan Built the Impossible 400 km Great Wall that You've Never Heard Of

Japan's tsunami seawall construction: 400 kilometres of engineering built after March 11, 2011 destroyed everything that came before it. In one hour, 90% of Japan's existing seawalls failed. Engineers rebuilt the entire coastline — a $12.7 billion construction project running 400 kilometres, engineered to 14.7 metres height, sealed by 443 automated floodgates that close in under five minutes with no human action. This documentary covers the full engineering and construction process from first foundation stone to completed structure — including the 2022 live test when a real 7.4 earthquake triggered all 443 gates simultaneously. What's in this video: Why 90% of Japan's seawalls failed in one hour and how engineers rebuilt them How engineers constructed a 25-metre-deep foundation in an active surf zone How 443 floodgates are engineered to close in under 5 minutes from a seismic trigger How 60,000-tonne caissons were engineered 63 metres into Kamaishi Bay — a world record TIMESTAMPS: 📌 00:05 - The $12.7B Coastline Reconstruction 01:05 - Analysis of the 2011 Tsunami Failure 02:05 - Surveying and Foundation Modeling 03:55 - Deep Foundation & Surf Zone Construction 05:07 - Sheet Piling & Embankment Engineering 07:14 - Concrete Panel & Quality Control 09:41 - Crown Wall & Energy Redirection 10:47 - Tetropod Armor & Wave Dissipation 12:08 - Automated Seismic Floodgate System 13:47 - Cliff Anchoring & Caisson Engineering 15:31 - Seismic Testing & Final Performance 16:10 - Emergency Routes & Public Promenade Subscribe to NEXTGEN MANUFACTURING to understand the incredible machines, blueprints, and megaprojects that built our world. #TsunamiWall #Megaprojects #HowItsMade #Japan #FactoryTour #Engineering #CoastalEngineering #Construction #InsideTheFactory #JapanEngineering #Tsunami #FullProcess #Aviation #Trending ⚠️ IMPORTANT: ABOUT THIS VIDEO ------------------------------------------------------------------- This is an educational documentary analyzing the engineering