Speaking of travel, have you ever been to Australia?
Literal
Travel [quotative-と] speaking-of, you [topic-は] Australia [to-に] gone [experience-ことがありますか]?
~と言えば (speaking of X) is a topic-shifting expression that introduces a related subject. ~たことがある (have the experience of doing X) is the standard pattern for asking about past experiences — one of the most useful conversational constructions.