Complex sentence: Tsushima is the closest Japanese territory to the Korean Peninsula, lying approximately 50 km from Busan (Pusan); on a clear day, the hills and mountains of the Korean peninsula are visible from the higher elevations on the two northern mountains.
Split into simpler sentences: Tsushima is the closest Japanese territory to the Korean Peninsula, lying approximately 50 km from Busan (Pusan). On a clear day, the hills and mountains of the Korean peninsula are visible from the higher elevations on the two northern mountains.