The Flood Protection System is an award-winning invention by Kilian Günthner that introduced a passive, self-activating approach to protecting doors and windows from floodwater. Inspired by the absorbent polymers used in diapers, the system uses superabsorbent material that expands on contact with water, sealing gaps automatically without electricity, mechanical deployment, or human intervention. Developed after severe rainfall caused water to enter his family home, the invention turned a practical household problem into a novel product design solution. Major institutions like LANXESS AG, Wallburger GmbH, and the University of Cologne invited Kilian to further develop the project. The project received recognition through Germany’s Jugend forscht competition, earned the Nicolaus August Otto Special Prize for Innovation, was covered by major newspapers, and led to Kilian being invited to sign the Golden Book of the City of Cologne.