If I had to pick Korea's best running courses

I think it's the Han River in Seoul and the Mipo line in Haeundae, Busan.
There are plenty of things to see along the large river currents, and the parks are well-developed.
Running along the coastal path from Haeundae Mipo to Songjeong makes you feel so refreshed.
The best part is that you can run intensely in the summer and immediately cool down by jumping into the Haeundae sea.
It's pure bliss... After coming out, air-drying in the sun, and having an iced americano on a cafe terrace, it's game over...