。
My father has never been abroad.
Literal
Father [topic-は] once [even-も] foreign-country [toward-へ] went fact [subject-が] not-exist.
Combines two patterns: 一度も~ない ('not even once') and ~たことがない ('have never done'). Together they're emphatic: 'has not once had the experience of going abroad.' 外国 is a general term for 'foreign country.'