UNESCO has listed a series of Koguryo burial sites on the world heritage list.
Here is a link to the list approved in 2004 (with coordinates for Google Earth):
Here is a list of accepted and “wait-listed” projects:
Here is a nice video of the sites on the UNESCO web page:
Here is a story in the BBC about North Korea’s additions to the World Heritage List.
Here is another great resource about the history of the move in the Korea Foundation Newsletter.
Apparently the job of overseeing these tombs is in the hands of the Management Bureau for Cultural Property Conservation (MBCPC) in the Korean Cultural Preservation Agency (KCPA)