A pool is a structure filled with water, designed for swimming, recreation, or exercise. Pools can be found in various settings, including private backyards, hotels, and public facilities. They come in different shapes and sizes, such as rectangular, circular, or freeform, and can be made from materials like concrete, fiberglass, or vinyl. Pools often include features like ladders, diving boards, and lighting for nighttime use. They require regular maintenance, including cleaning and chemical balancing, to ensure safe and enjoyable swimming conditions. Many people enjoy pools for relaxation, socializing, or fitness activities like water aerobics and lap swimming.