硫黄
acid
asia
beppu
boiling
danger
destination
environment
famous
flowing
fumarole
gas
geological
geology
geothermal
heat
hell
hot
japan
japanese
jigoku
kyushu
landscape
mineral
mud
natural
nature
oita
oita prefecture
onsen
outdoor
place
pond
pool
sea
smoke
spa
spring
steam
stone
sulfuric acid
temperature
thermal
tourism
travel
umi
unpleasant smell
volcanic
water