A cistern is a waterproof receptacle used for collecting and storing rainwater or other liquids. Typically found underground or in basements, cisterns can be made from various materials, including concrete, stone, or plastic. They are often used in areas where water supply is limited or for irrigation purposes. Cisterns have been used since ancient times, with examples found in civilizations such as the Romans and Greeks. In modern times, they are still utilized in many regions, especially in arid climates, to conserve water and provide a reliable source for domestic or agricultural use.