Ngo Mon was constructed in 1833 during the reign of Emperor Minh Mang. The gate leads to the Imperial Palace and was the observation point for the Emperor to review his troops and for ceremonial use.

Midday Gate is divided into two levels. At ground level, the gate actually has five entrances. The one in the center is used only by the king. On each side are two entrances used by mandarins, soldiers and horses. On the second level is Lau Ngu Phung - the Five-Phoenix Pavilion. The king reviewed his troops and subjects under the center hall of the pavilion. The roof of this hall is covered with gold enameled tiles. The two halls flanking the center hall were reserved for other members of the court.