This is the 956th most frequent Korean word.
한국을
"한국을" means "Korea" as the object of a sentence (using the object marker 을).
한국을 refers to the object of the action, in this case, 'travel'.
저는 한국을 여행하고 싶어요.
I want to travel to Korea.
한국을 is used as the destination of the verb 'visit'.
많은 사람들이 한국을 방문합니다.
Many people visit Korea.
한국을 acts as the object being considered in the context of the verb 'considers'.