The Independence Hall of Korea is Cheonan's heavyweight sight: a large museum complex about Korean national history, with its sharpest focus on resistance to Japanese colonial rule. The scale is part of the experience, from the broad plazas and monuments outside to the sequence of exhibition halls inside.
It is not a neutral little local museum, and that is worth knowing before you go. The tone is patriotic and sometimes blunt, but the subject matters deeply in Korea, and the exhibits help explain why colonial memory still shapes politics, schoolbooks, and public monuments.