英文關鍵字
active
attraction
bubbles
dirty
dramatic
earth
ecology
enviroment
environment
erupting
eruption
extreme
geological
geology
geothermal
gray
ground
gurgling
hillside
hot
land
landscape
liquid
mud
muddy
national
natural
nature
nobody
outdoor
outside
park
phenomena
phenomenon
pool
power
steam
temperature
texture
textured
toxic
travel
underground
vent
volcano
volcanoes
wet
wyoming
yellowstone