Sinmumun Gate, the northern palace gate, protected Gyeongbokgung Palace from attacks from the north. It features a single entrance and one story pavilion.
Construction on the stone gate first started in 1433 during the reign of King Sejong. He ruled from 1418 to 1450 as the fourth king of the Joseon Dynasty.
The gate was named in 1475 by King Seongjong.
Like many other structures, the gate was destroyed by the Japanese during their invasion in 1592.
The gate was not rebuilt until 1865. This was around the same time when the palace was being rebuilt by Prince Regent Heungseon Daewongun.
Sinmumun is one of four gates surrounding the palace. In total, the palace has 2,404 meters (7,887 feet) of walls. The other three gates are Gwanghwamun, Geonchunmun, and Yeongchumun.
The area was closed to the public from 1961 until 2006 because of security concerns due to its location near the Cheong Wa Dae (Blue House), the residence and office of the president of Korea.