The Great South Gate is one of the best-preserved remnants of Tainan's historic city walls, built during the Qing dynasty and dating in its current form to the early 19th century. The gate retains an unusual feature for a Chinese city gate: a secondary circular entrance, called a moongate, sitting next to the main arched gateway. The Japanese colonial administration demolished much of the wall when building modern roads through the city, but preserved several of the gates as historical monuments, and the Great South Gate survived with more of its surrounding wall section intact than most.
The gate sits in a small park at the southern edge of the old city, shaded by a large banyan tree that has grown up around the masonry over the past century. It's a quieter site than the main attractions and gives a better sense of how the city once functioned as an enclosed, fortified space. The nearby Duiyue Gate and sections of the surviving city wall are a short walk away for those interested in Tainan's fortification history.