The Han River is one of Korea’s largest, and it goes right through the center of Seoul. Along the banks of the river, throughout most of the city, is a lovely recreational area set aside for exercising and sports.
Away from the boisterous highway, you can rent a bicycle and slowly pedal up and down the river or go for a lengthy ride on the track that goes for over 40 kilometers. If biking is not your thing, you may want to check out a Seoul night tour for views of the river at night or even a Han river boat cruise.