People have most likely been submerging themselves in hot water since, well, before they were people; just look at those adorably furry Japanese macaques chilling out in snowy mountain onsen. We might have evolved past all that body hair, but soaking in hot water still feels good.

Natural mineral hot springs burbling out of volcanic mountains are one thing, but stand-alone Jacuzzi tubs are something else entirely. Given their popular reputation as a site of swinging ’60s, quaalude-fueled romps, perhaps no one will be surprised to learn that the modern hot tub was invented in California. But the story behind that invention is as wholesome as apple pie. After immigrating to the US in the early 20th century from rural northwest Italy, Candido Jacuzzi settled with his parents and 12 siblin...