About 20,000 years ago, an eruption of Mt. Nantai created Lake Chuzenji at its foot. At an altitude of 1,269 meters, Chuzenji is Japan’s highest natural lake, with a 25-kilometer hiking trail along its perimeter. During the 19th and 20th centuries it was a popular summer resort for villas owned by foreigners and embassies. The landscape includes blooming azaleas in early summer and bright foliage in autumn.