Unzen Jigoku

Field of volcanic vents east of Nagasaki where steam and sulfurous gas hiss from around 30 bubbling pools set in pale white clay. The landscape looks genuinely otherworldly, all heat and acid and mineral color. Between 1627 and 1632, Christian martyrs were executed here, and a monument at Oito Hell marks where they died. A winding path leads through the entire field, and the walk takes about 30 to 40 minutes at an easy pace. At the far end, a free outdoor foot bath lets you soak after the walk, and a small shop sells snacks and souvenirs. Unzen Onsen, the surrounding hot spring resort, became popular with both Japanese and foreign visitors during the Meiji era and retains a quiet, old-fashioned character.