As Ian said, you need to use "its" (possessive pronoun) rather than "it's" (contraction.) I just want to point out that you've both capitalized every word in the sentence. Only capitalize the first word of a sentence and then any proper nouns that there might be. In this case since the the only proper noun is also the first word, "Cuba" is the only word that should be capitalized.

No, Você não usa o apóstrofo neste caso. "It's" = It is "Its" = ownership / possession "Cuba Is Famous For Its Cigars" Good luck!