gyeongbokgung was the largest palace of the joseon dynasty.
it was first built in 1394 by king taejo and many kings lived here.
at its largest,the palace had 300 buildings with 5,792 rooms.
today it has about 10 buildings and is open to everyone.

다른 부분은 괜찮은데, at its largest를 어떻게 해석해야 될지 모르겠습니다 ㅠㅠ
at its largest palace에서 palace를 뺀 건가 하고 생각하니, 궁전이 뒤에 바로 나오고..
its가 뭘 가르키는 건가요??

꼭 좀 답변 부탁드립니다~
그럼 감사합니다^^