"Hearst Castle"
Underground [ish] pool was said to have been used by the servants there; so the Tour Guide claimed, saying the Hearst guests didn't like it. Beautiful Venetian tiles.
https://en.wikipedia.org/wiki/Hearst_Castle
"The Neptune Pool patio features an ancient Roman temple front, transported wholesale from Europe and reconstructed at the site. "
Neptune Pool ; site "Hearst Castle"
was used by Hearst family after giving it to State of California - part of the arrangement.
Hearst = first king of Fake News.
Notice how there is no room to lounge around the edge which is the same design as evident at the VanderBilt pool Casa Loma castle pool.