Sungnyemun Gate is Korea’s National Treasure No. 1, and its unofficial name is Namdaemun Gate. Sungnyemun Gate is the largest castle gate stone structure with an arched entrance in the middle. There’s a column on top of a platform, raising the roof, distinguishing the upper stories and lower stories of the building. A passageway for traffic is located at the east and west ends of the gate.

Different from the other gates, Sungnyemun’s tablet has its name written vertically.

When the first king of Joseon Dynasty, Lee Seong-Gye (reign 1335-1408), had constructed the capital city, he believed that fire will reach to Gyeongbokgung Palace as well as the capital city as Mt. Gwanaksan of Seoul is shaped like fire according to feng-shui principles. Sungnyemun’s name means fire, which is from the harmony of the Five Elements and if written vertically, the Chinese character ‘fire’ looks as if it is providing protection. This was Taejong’s (1367-1422) first son, Yangnyeongdaegun’s (1394-1462) famous writing.

On February 10, 2008, Sungnyemun was destroyed by fire. After a 5-year reconstruction work, the gate has been re-opened to the public again as of May 4, 2013.

More Info: en.wikipedia.org