A Swimming Pool is a structure holding swimming-enabled water (either chlorine or salt water) for leisure or sporting activities. Pools are built into the ground are most commonly constructed from materials such as concrete, natural stone, metal, plastic or fiberglass, and can be customized to shape and size.
Many health clubs, fitness centers and private clubs, such as the YMCA, have pools used mostly for exercise or recreation. Many towns and cities provide public pools. Many hotels have pools available for their guests to use at their leisure. Educational facilities such as universities typically have pools for physical education classes, recreational activities, leisure or competitive athletics such as swimming teams. Hot tubs and spas are pools filled with hot water, used for relaxation or hydrotherapy, and are common in homes, hotels, and health clubs. Special swimming pools are also used for diving, specialized water sports, physical therapy as well as for the training of lifeguards and astronauts. Swimming pools may be heated or unheated.