Namdaemun, officially known as the Sungnyemun, is one of the Eight Gates in the Fortress Wall of Seoul, South Korea. The gate formed the original southern boundary of the city during the Joseon dynasty, although the city has since significantly outgrown this boundary. It is located in Jung-gu between Seoul Station and Seoul Plaza, with the historic 24-hour Namdaemun Market next to the gate.

The Eight Gates of Seoul are a series of historic gates located in Seoul, South Korea. Two of the gates are now destroyed, although the others are still standing. The gates were constructed between 1396 and 1398, and allowed access to the city, which was surrounded by the Fortress Wall during the Joseon period.