I was thinking of the San Simeon swimming pool. There are larger more spectacular pools. The definition of a swimming pool includes human-made lagoons. That largest one is in Egypt. It had a price tag of $5.5 billion, according to one article. I do find out that there are at least 66 million gallons of water. It covers 23.9 acres.
For North Americans, there is the Lagoon at Epperson Florida (built by Crystal Lagoons), and the Hard Rock Guitar Motel in Hollywood, Florida. Hard Rock Guitar Hotels are the stand-out with the amazing guitar-shaped hotel structures. There seem to be Hard Rock hotels everywhere in the world.
Did you know that Bronte Creek Provincial Park in Oakville is listed as one of the largest water pools, created in 1972. It is 1.8 acres. It is now closed for renovations/rebuild.
How much does it cost to maintain a pool? Forbes says that on average it costs $180 a month to keep a pool in use for us normals. For the world's largest pool? One article says $4 million annually. But I wonder about that, don't you? It seems low.
The company making most of these "crystal lagoons" is named Crystal Lagoons. There are projects everywhere, and especially int he U.A.E and Dubai. The project's architecture firm is Arquitectonica, based in Miami.