Swimming pool
A swimming pool, swimming bath, wading pool, paddling pool, or simply pool, is a man-made structure designed to hold water to enable swimming and associated activities. Pools can be built into the ground or built above ground, and may be found as a feature aboard ships. In-ground pools are most commonly constructed from materials such as concrete, natural stone, metal, plastic, composite or fiberglass, and may follow a standardized size, the largest of which is the Olympic-size swimming pool, or be of a custom shape.
Many health clubs, fitness centers, and private clubs have pools for their members, often used for exercise. In much of the world, local governments provide publicly-run pools. Some of these are outdoors; indoor pools are often part of a leisure centre. Many hotels have a pool for the use of their guests. Pools as a feature in hotels are more common in tourist areas or near convention centers. Many universities and other institutional communities provide pools for their members, often as part of an institution-specific athletic or recreational complex. Apartment complexes and residential subdivisions may provide a pool for the use of their residents. Private residences, particularly in areas with warm climates, may have their own pools.
Educational facilities such as high schools and universities often have pools for physical education classes, recreational activities, leisure, and competitive athletics such as swimming teams. Hot tubs and spas are small heated pools used for relaxation or hydrotherapy. Specialised pools are also used for diving, water sports, and physical therapy, as well as for training of lifeguards and astronauts. Swimming pools most commonly use chlorinated water, or salt water, and may be heated or unheated.
History
Pre-modern
The "Great Bath" at the site of Mohenjo-Daro in modern-day Pakistan was most likely the first swimming pool, dug during the 3rd millennium BC. This pool is, is lined with bricks, and was covered with a tar-based sealant.Ancient Greeks and Romans built artificial pools for athletic training in the palaestras, for nautical games and for military exercises. Roman emperors had private swimming pools in which fish were also kept, hence one of the Latin words for a pool was piscina. The first heated swimming pool was built by Gaius Maecenas in his gardens on the Esquiline Hill of Rome, likely sometime between 38 and 8 BC. Gaius Maecenas was a wealthy imperial advisor to Augustus and considered one of the first patrons of arts.
Ancient Sinhalese built a pair of pools called "Kuttam Pokuna" in the kingdom of Anuradhapura, Sri Lanka, in the 6th century AD. They were decorated with flights of steps, punkalas or pots of abundance, and scroll design.
19th and 20th centuries
Swimming pools became popular in Britain in the mid-19th century. As early as 1837, six indoor pools with diving boards existed in London, England. The Maidstone Swimming Club in Maidstone, Kent is believed to be the oldest surviving swimming club in Britain. It was formed in 1844, in response to concerns over drownings in the River Medway, especially since would-be rescuers would often drown because they themselves could not swim to safety. The club used to swim in the River Medway, and would hold races, diving competitions and water polo matches. The South East Gazette July 1844 reported an aquatic breakfast party: coffee and biscuits were served on a floating raft in the river. The coffee was kept hot over a fire; club members had to tread water and drink coffee at the same time. The last swimmers managed to overturn the raft, to the amusement of 150 spectators.The Amateur Swimming Association was founded in 1869 in England, and the Oxford Swimming Club in 1909. In 1939, Oxford created its first major public indoor pool at Temple Cowley.
File:Helen-Gould-Lyndhurst-Pool-c-1920.jpg|thumb|left|Swimming pool at Lyndhurst estate in Tarrytown, New York, United States, constructed in 1911. Known as "Helen's Bath," it was built by the estate owner, prominent philanthropist Helen Miller Shepard, who opened it to the public. The pool had full-time lifeguards ; swimming instructions were provided to local boys and girls.
The modern Olympic Games started in 1896 and included swimming races, after which the popularity of swimming pools began to spread. In the US, the Racquet Club of Philadelphia clubhouse boasts one of the world's first modern above-ground swimming pools. The first swimming pool to go to sea on an ocean liner was installed on the White Star Line's Adriatic in 1906. The oldest known public swimming pool in the U.S., Underwood Pool, is located in Belmont, Massachusetts.
File:Yrjonkadun-uimahalli-1928.jpg|thumb|The Yrjönkatu Swimming Hall, the oldest swimming hall in Finland, photographed on its opening day on 4 June 1928 in Kamppi, Helsinki
Interest in competitive swimming grew following World War I. Standards improved and training became essential. Home swimming pools became popular in the United States after World War II and the publicity given to swimming sports by Hollywood films such as Esther Williams' Million Dollar Mermaid made a home pool a desirable status symbol. More than 50 years later, the home or residential swimming pool is a common sight. Some small nations enjoy a thriving swimming pool industry.
A two-storey, white concrete swimming pool building composed of horizontal cubic volumes built in 1959 at the Royal Roads Military College is on the Canadian Register of Historic Places.
World records
According to the Guinness World Records, the largest swimming pool in the world is San Alfonso del Mar Seawater pool in Algarrobo, Chile. It is long and has an area of 8 ha. At its deepest, it is deep. It was completed in December 2006.The largest indoor wave pool in the world is at DreamWorks Water Park within the American Dream shopping and entertainment complex at the Meadowlands Sports Complex in East Rutherford, New Jersey, United States, and the largest indoor pool in North America is at the Neutral Buoyancy Lab in the Sonny Carter Training Facility at NASA JSC in Houston.
In 2021, Deep Dive Dubai, located in Dubai, UAE, was certified by the Guinness Book of World Records as the world's deepest swimming pool reaching. The Y-40 swimming pool at the Hotel Terme Millepini in Padua, Italy, previously held the record,, from 2014 until 2021.
The Fleishhacker Pool in San Francisco was the largest heated outdoor swimming pool in the United States. Opened on 23 April 1925, it measured and was so large that the lifeguards required kayaks for patrol. It was closed in 1971 due to low patronage.
In Europe, the largest swimming pool opened in 1934 in Elbląg, providing a water area of.
One of the largest swimming pools ever built was reputedly created in Moscow after the Palace of Soviets remained uncompleted. The foundations of the palace were converted into the Moskva Pool open-air swimming pool after the process of de-Stalinisation. However, after the fall of communism, Christ the Saviour Cathedral was re-built on the site between 1995 and 2000; the cathedral had originally been located there.
The highest swimming pool is believed to be in Yangbajain. This resort is located at AMSL and has two indoor swimming pools and one outdoor swimming pool, all filled with water from hot springs.
Dimensions
Length: Most pools in the world are measured in metres, but in the United States pools are often measured in feet and yards. In the UK most pools are calibrated in metres, but older pools measured in yards still exist. In the US, pools tend to either be 25 yards, 25 metres or 50 metres. US high schools and the NCAA conduct short course competition. There are also many pools m long, so that 3 lengths = 100 m. This pool dimension is commonly used to accommodate water polo.USA Swimming swims in both metric and non-metric pools. However, the international standard is metres, and world records are only recognized when swum in 50 m pools but 25-yard pools are very common in the US. In general, the shorter the pool, the faster the time for the same distance, since the swimmer gains speed from pushing off the wall after each turn at the end of the pool.
Width: The width of the pool depends on the number of swimming lanes and the width of each individual lane. In an Olympic swimming pool each lane is 2.5 meters wide and contains 10 lanes, thus making the pool 25 meters wide.
Depth: The depth of a swimming pool depends on the purpose of the pool, and whether it is open to the public or strictly for private use. If it is a private casual, relaxing pool, it may go from deep. If it is a public pool designed for diving, it may slope from in the deep end. A children's play pool may be from deep. Most public pools have differing depths to accommodate different swimmer requirements. In many jurisdictions, it is a requirement to show the water depth with clearly marked depths affixed to the pool walls, although this may not be the case for private pools in some jurisdictions.
Types
Pools can be either indoors or outdoors. They can be of any size and shape, and inground or above ground. Most pools are permanent fixtures, while others are temporary, collapsible structures.Private pools
Private pools are usually smaller than public pools. Home pools can be permanently built-in, or be assembled above ground and disassembled after summer. Privately owned outdoor pools in backyards or gardens started to proliferate in the 1950s in regions with warm summer climates, particularly in the United States with desegregation. A plunge pool is a smaller, permanently installed swimming pool.Construction methods for private pools vary greatly. The main types of in-ground pools are gunite shotcrete, concrete, vinyl-lined, and one-piece fiberglass shells. In recent years, a newer construction approach known as the "hybrid" system has been introduced, with prefabricated modular components manufactured in factories.
Many countries now have strict pool fencing requirements for private swimming pools, which require pool areas to be isolated so that unauthorized children younger than six years cannot enter. Many countries require a similar level of protection for the children residing in or visiting the house, although many pool owners prefer the visual aspect of the pool in close proximity to their living areas, and will not provide this level of protection. There is no consensus between states or countries on the requirements to fence private swimming pools, and in many places they are not required at all, particularly in rural settings.