Japanese onsens are natural hot springs that have been a part of Japanese culture for centuries, with varying temperatures ranging from 25 to over 50 degrees Celsius. Visitors can choose which pool they prefer based on their personal preference and gradually adjust to the heat. Soaking in an onsen has several health benefits, including relaxation, improved circulation, relief from muscle and joint pain, and skin health. Visitors should be aware of proper etiquette and safety concerns when visiting an onsen.