Swimming is one of the most popular pastimes in the world. It is also one of the oldest. As an organized activity, swimming dates back to 3rd century BC. The Great Bath at Mohenjo-Daro in modern Pakistan is believed to be the first the swimming pool.
In 1st century BC, the first heated swimming pool was built by Gaius Maecenas, a friend of the first emperor of Rome. The first swimming club is established in 1844 and indoor swimming pool in 1862. In 1896, swimming was included in the first modern Olympics held in 1896.
Later, swimming pools are constructed on different places. In 1907, the first above-ground swimming pool is built at the Racquet Club of Philadelphia. The largest swimming pool in the world located in Algarrobo, Chile. According to the National Swimming Pool Foundation estimations, currently there are over 10 million swimming pools in the US.