The D.F.S Dragonfly Sanctuary is a structure placed in concrete riverbanks to provide a refuge and breeding site for dragonflies after habitat loss, helping to restore the river ecosystem. It uses small openings to protect larvae from fish, potentially boosting survival rates by 50%. This increases the adult dragonfly population, which in turn acts as biological pest control, reducing the need for chemical pesticides and lowering carbon emissions. The D.F.S is made with 3D-printed concrete that sequesters approximately 18.8 grams of CO2 during production.