A bit of Swimming Pool History
Swimming pools accordingly to Archaeological Discoveries have been built since 2500BC, however this is just what was found until now.
The "Great Bath" at the site of Mohenjo-Daro in modern-day Pakistan was most likely the first swimming pool. This pool is 12 by 7 metres, is lined with bricks, and was covered with a tar-based sealant. (Wikipedia)
Swimming Pools where intended, as now days for different occasions. So the Pakistan Swimming pool, is considered to be used as spiritual Bath. However, the Greek Swimming Pool, dated 750 BC and Roman Pool, dated 100AD, were intended as a Public Bath.
Also, 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 of Rome in the 1st century BC. Gaius Maecenas was a rich Roman lord and considered one of the first patrons of arts.
Ancient Sinhalese built pairs of pools called "Kuttam Pokuna" in the kingdom of Anuradhapura, Sri Lanka in the 4th century BC. They were decorated with flights of steps, punkalas or pots of abundance, and scroll design.