Mount Fuji Mountain in Kanagawa Prefecture, Japan. Fuji Volcano has been registered by UNESCO as a World Heritage Site. It is the 17th World Heritage Site of Japan. Japan’s Mt. Fuji is an active volcano about 100 kilometers southwest of Tokyo. Commonly called “Fuji-san,” it’s the country’s tallest peak, at 3,776 meters. A pilgrimage site for centuries, it’s considered one of Japan’s 3 sacred mountains, and summit hikes remain a popular activity.