Unzen Onsen

Unzen Onsen sits at 700 meters elevation in the volcanic mountains of the Shimabara Peninsula and was designated as Japan's first national park in 1934. The town's centerpiece is Unzen Jigoku, a stark landscape of roughly 30 steam vents, bubbling mud pools, and fumaroles where temperatures reach 120 degrees Celsius, all accessible via well-maintained walking paths. In the 17th century these hells were infamously used as a site of Christian persecution, and informational plaques along the trails recount this somber history. The hot spring resort developed in the 19th century as a summer retreat for foreign residents of Nagasaki and Shanghai, giving it an unusually cosmopolitan heritage among Japanese onsen towns. Today visitors can enjoy the strongly acidic sulfur springs at numerous hotels and public bathhouses, purchase onsen tamago eggs cooked in the natural hot springs, and hike to the summit of nearby Mount Fugen for panoramic views of the peninsula and Ariake Sea.