These hexagonal chimneys, built in 1865 behind the Queen's quarters in the Gyeonbokgung Palace, were designed to draw smoke from the fires that heated the interior floors. Although my apartment doesn't have such beautiful brick chimneys containing ornamental designs such as the phoenix, crane, bamboo, and pine, it shares in the underfloor heating system known as Ondol. Such heating on the footsies was welcomed by royalty as well as modern cold-footed people such as myself. In a country where taking off one's shoes before entering a home is common practice, along with sleeping on a mattress on the floor, such heat is particularly appreciated in the cold months. While the old system caused a constant threat of fire and carbon monoxide poisoning for the palace buildings & residents, the modern electrical system in my apartment is very safe. Ondol heating, according to this article, is catching on worldwide. It states that 50% of European buildings have ondol installed. This ancient technology is also being utilized in some airports and roads to melt snow and reduce noise.