Since Korea has hot summers and cold winters, the 'Ondol(Gudeul),' a floor-based heating system, and 'Daecheong,' a cool wooden-floor style hall were devised long ago to help Koreans survive the frigid winters and to block sunlight during summer. These primitive types of heating and air-conditioning were so effective that they are still in use in many homes today¹). The posts, or 'Daedulbo' are not inserted into the ground, but are fitted into the corner stones to keep Hanok safe from earthquakes.