The question is not well asked.
There are two meanings of "country". One is "State" the other is "countryside". Both reading are possible. There is no need to say "foreign country" or similar, though this can prevent ambiguity
In the first sense you would probably use "a", and so no correction is needed.
In the second sense you would probably use "the" and insert a comma. You would also probably use "countryside" to avoid ambiguity.
I spent my holiday in the countryside, which is peaceful and picturesque.
However as asked the question is unanswerable, because there is nothing in the sentence that needs changing.