This is the 7765th most frequent Korean word.
한강
Han River.
The word '한강' is used here as the proper noun naming the river itself.
한강은 서울을 가로지르는 강이에요.
The Han River is a river that flows through Seoul.
In this sentence, '한강' refers to the location or area around the river.
한강에서 자전거를 타면서 경치를 구경했어요.
I rode a bicycle along the Han River while enjoying the scenery.
Here, '한강' is mentioned as the subject whose specific characteristic (night view) is being described.