A cistern is a waterproof receptacle used for collecting and storing rainwater or other liquids. They are often found in areas where water supply is limited, providing a reliable source of water for drinking, irrigation, or other uses. Cisterns can be made from various materials, including concrete, stone, or plastic, and can vary in size from small household units to large underground tanks. Historically, cisterns have been used in many cultures, including ancient Rome and Greece, where they played a crucial role in water management. Today, they are still utilized in many regions, especially in arid climates, to help conserve water and promote sustainability.