Ngo Mon, the three-entrance gate in front of the Thai Hoa Palace, which houses the thrones of the 13 emperors in the Nguyen Dynasty from Gia Long to Bao Dai, was built between 1833 and 1840 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.

The gate's first floor is named Lau Ngu Phung (Five Phoenix Mansion), where the king reviewed his troops and subjects under the center hall of the mansion. The ground floor has three entrances, one being for the king and two on both sides for mandarins and soldiers.

On August 30, 1945, the gate was the venue for the abdication ceremony of Bao Dai, the last king of Vietnam. Today, Ngo Mon and other parts of the royal city are seen as priceless remnants of Vietnam's cultural heritage. The worldwide interest in this heritage has led to many local and foreign investors focusing on Hue as a good place to service the tourism industry.