How America Built a $14.5B Wall to Stop the Next Katrina

After Hurricane Katrina, America spent $14.5 billion building a wall to protect New Orleans. Eleven months after it was finished, its own engineers announced it was already sinking. This is the engineering story of the New Orleans flood protection system and the Lake Borgne Surge Barrier: 1,271 giant concrete piles driven into the marsh, steel gates weighing more than 675 tons each, and one of the largest drainage pump stations ever built. It begins with the strangest fact about Katrina: in the places that failed first, the water never went over the walls. It follows the engineers who rebuilt the system around one idea, closing the doors where the surge comes in, and the night in 2021 when Hurricane Ida tested it, 16 years to the day after Katrina. And it ends with what the official reports say about the limits of a "100-year" standard, a coast that keeps sinking, and a neighborhood that never came back. 🔔 Subscribe to Impossibly Engineered for a new engineering documentary every week. Real megaprojects, real numbers, and the true stories of how they were built.