Tainan's Tian Tan (Altar of Heaven) is—true to its name—a place to worship the heavens. Tian Tan is dedicated to the Jade Emperor, commonly known as Tian Gong (Heavenly Father), Heaven, or His Majesty the Jade Emperor. The Jade Emperor is the supreme deity of Taiwan's folk religion, and as such, Tian Tan and the Founding Jade Emperor Temple enjoy a high religious status in Tainan. Tian Tan is located in the area once called ""Tiangongcheng"" (""Jade Emperor's Ground""). According to legends, Koxinga (1624-1662 CE), Prince of Yanping, built an altar dedicated to the Jade Emperor at this site on the 12th lunar month in the 15th year of Yongli Emperor's reign in the Ming era (1661 CE). Locals installed an incense burner at the altar in the early Qing era, and in the 4th year of Xianfeng Emperor's reign in the Qing era (1854 CE), officials and locals raised funds to first build the front gate and main hall, and then the rear hall the following year. Renovations were conducted throughout the years, forming the layout we see today, consisting of three main structures, two hallways, and Wusheng Hall to the left. One of the three famed plaques of Tainan, the plaque that hangs above Tian Tan's main hall simply reads ""One"". On the eaves is a stone inscribed with ""Big!"". Together, the Chinese characters for ""one"" (一) and ""big"" (大) form the word ""tian"" (天), or ""sky"", which symbolizes people's praise to the heavens.
The panels of Sanchuanmen do not paint door gods, but nail door nails. The total number of door nails is 108.
In the Temple of Heaven, there are often students chanting scriptures to pray for the people
In front of the wall on the left side of the apse, the Tianshi of Zhangfu is enshrined. Tainan has the custom of welcoming and sending off the Tianshi.
The Mingjian shrine in the apse is dedicated to the ancestors of the Three Qing Daoists and is the supreme god of the Taoist gods.
The main hall is towering, with a "Da Zai" stone inlaid on the top. The original monument is a cultural relic during the Xianfeng period of the Qing Dynasty. It has now been moved to the temple for display
In the four corners of the main hall, there is a Hanfan carrying the frame, called the "Hanfan Qingda fir", which is one of the features of Tainan's early temple architecture.
A plaque dedicated to President Jiang Zhongzheng (1887-1975) is hung above the shrine in the main hall to show respect for the sky
The plaque with the word "一" is known as the three famous plaques of the city
The main deity of the Temple of Heaven is the Jade Emperor God. Folk beliefs believe that there is no specific image of heaven that can be shaped into a god, so the Temple of Heaven enshrines the gods.