Kusatsu Onsen is a famous hot spring resort in Gunma prefecture, Japan, known for its high-quality hot spring water with medicinal properties. It’s one of the oldest hot spring resorts in Japan and attracts millions of tourists every year. The resort is surrounded by scenic mountain views, and guests can enjoy hot spring baths in traditional ryokans (inns) or more modern facilities. There are also several walking paths and hiking trails in the area for those who want to explore the surrounding nature.