Great Bath at Mohenjo-Daro; currently in modern Pakistan is the first ever swimming world ever saw. Made in the 3rd millennium BC, the pool till date is called the first swimming pool. Greeks, Romans and many more civilizations got these made but with different intention altogether. It was not solely for bathing. Some used it to encourage sports and some used it for bathing specifically but dwelled fishes in it.
The largest swimming pool of the world is located in Chile. Initially the largest pool was considered to be the one in Moscow. Though many still perceive it to be a symbol of luxury, but in real sense it is not that big a deal to have it at your place. You may have it the way you want it.
There are swimming pools for your backyards that come in a number of varieties. Yes the portable swimming pool are efficient but nothing will add to the beauty more than the permanent ones. From geometrically perfect shapes to abstract shapes like amoeba, you may create it as per your choice.
If you are the kind who loves to celebrate in private, then backyard swimming pools are the perfect thing for you. Relax, exercise, read beside, do anything you want to.