a river river or palace palace???

For some reason, I keep seeing things like this in Korea. When written in English, they use the full Korean name of something and then add what it is afterwards, even though it is already part of the name. For example, 'gang' is river. The Hangang is the main river going through Seoul. For some reason, it is often called the Hangang River. Why??? It isn't the Han River River. Then there are the many palaces around the country. 'Gung' is palace. Why do they always say Changdeokgung Palace, Gyeongbokgung Palace, etc??? Silly.