국경을

the border

→ 국경
phrase Rare #32,281
the border 을 marks 국경 (border) as the object of the sentence. It often appears with verbs meaning “cross” or “approach.”
KO: 국경을 넘어 다른 나라로 갔어요.
EN: I crossed the border into another country.

국경을 넘어야 해요

I have to cross the border.

— 이중 배상 (1944)