Do you know Japanese Onsen? It's a hot springs and they are all over Japan. Hot springs is one of my favorite things to do. It warms you up in the fall and winter, and it refreshes you in the humid Japanese summer.
I guess people in most Western countries (except for Russia) are not used to the tradition of group baths. The baths in Japan are separated by sex, and everyone goes in naked. In the old days, it was not so common for Japanese apartments to have a bath in them, so people would go to the public baths. You might go with your grandpa and scrub his back for him.
I miss hot springs and baths when I am in Los Angeles. They do have Korean Spas in the Koreatown area in LA, but it is not quite the same.
In Japan, hotsprings are a popular tourist destination, and if your town discovers a hot springs, suddenly it will have many visitors and tax dollars. Sometimes cities and hotels get in trouble for faking a hot springs. I like hot springs, but I am just a happy if it is just regular water, as long as the baths are handsome.