Swimming pool
noun - A swimming pool is a container filled with water intended for swimming or water-based recreation. There are many standard sizes including Olympic-size competitive swimming pools. A pool can be built either above or in the ground, and from materials such as concrete, metal, plastic or fiberglass.
Pools that may be used by many people or by the general public are called public, while pools used exclusively by a few people or in a home are called private. Many health clubs, fitness centers and private clubs have public pools used mostly for exercise. Many hotels have pools available for their guests. Hot tubs and spas are pools with hot water, used for relaxation or therapy, and are common in homes, hotels, clubs and massage parlors. Swimming pools are also used for water polo, diving and other water sports, as well as for the training of lifeguards and flight attendants.
Ocean pools
In the early 20th century, especially in Australia, ocean pools were built, typically on headlands by enclosing part of the rock shelf, with water circulated through the pools by flooding from tidal tanks or by regular flooding over the side of the pools at high tide. Swimming in these ocean pools provided security against both rough surf and sharks.
There are currently about 100 ocean baths in New South Wales in Australia that range from small pools roughly 25 meters long to the 50x100m baths in Newcastle.
