To improve the sentence structure, you should add a comma after "Greece" in the sentence:
"If you ever travel to Greece, be sure to visit the beautifully designed Acropolis Museum with its spectacular collection of ancient Greek artifacts."
This addition of a comma after "Greece" helps to separate the introductory clause "If you ever travel to Greece" from the main clause "be sure to visit the beautifully designed Acropolis Museum with its spectacular collection of ancient Greek artifacts." It enhances the flow of the sentence and clarifies the relationship between the two clauses.
