The Korean under-floor heating system(an Ohndol)

Korean had ubder-floor heating system. it is ondol. ondol is very warm. Korean people almost use to it because ondol is special heating system in Korea. In this system, heat goes under the floor to warm up the room. I'ts structure is unique.
It is made by materials that we can get easily in the nature, and it is very helpful to our body.
It is warm in the winter and coool in the summer.
As I said earlier, Ohndol is very special and traditional Korean heating system.
Ohndol is popular from abroad. Also, Ohndol is esport beyond the seas.