Answer: oldfaithful

AnswerCrossword Clue
OLDFAITHFULYellowstone attraction
OLDFAITHFULYellowstone geyser
OLDFAITHFULWyoming attraction
OLDFAITHFULYellowstone Park's big attraction.
OLDFAITHFULAttraction that operates under its own steam?