Namdaemun is commonly called name and it's official name is Sungnyemun.
Namdaemun is one of 8 gates in the Fortress wall of Seoul which surrouneded the city in Joseon dynasty long time ago.
Namdaemun was chosen to be the Korean Treasure No.1 in 1938 by the government.
Namdaemun was burnt in 2008 but the restoration was completed 29th April 2013