Beppu, Japan
Credit: Franck Guiziou / Getty Images

The city of Beppu in southern Japan is home to countless onsen, natural hot springs used for bathing. Locals claim the springs are cure-alls for maladies ranging from skin conditions to digestive problems to neurological disorders. We can't vouch for any of the medical claims, but there's no denying a good, hot soak feels pretty good. Beppu also has eight boiling pools lovingly referred to as jigoku (hells), and as their name indicates, they're much too hot to enter, with temperatures topping 200 F in some places.