A swimming pool, swimming bath, wading pool, paddling pool, or simply pool is a structure designed to hold water to enable swimming or other leisure activities. Pools can be built into the ground or built above ground, and may be found as a feature aboard ocean-liners and cruise ships. In-ground pools are most commonly constructed from materials such as concrete, natural stone, metal, plastic, or fiberglass, and can be of a custom size and shape or built to a standardized size, the largest of which is the Olympic-size swimming pool.
