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. Passageways for traffic are located at the east and west ends of the gate. Different from the other gates, Sungnyemun Gate’s tablet has its name written vertically.