South Gate Tower is the south gate (also called scarlet bird gate) of the four gates around the Emperor`s graveyard. It has two sets of tri-platforms, which are symmetrically connected. It is the largest, the earliest and the most superior gate tower of Emperor`s graveyard ever discovered. The exterior of the Protection Hall was modeled after the gate tower of the Han Dynasty, which  protects the ruins and at the same time reflects the grandeur and the panorama of the tri-platform gate tower used exclusively by the Emperor. Visitors can also learn in the 3000sqm hall about the historical development of gate tower construction in the different dynasties in China.