Cheonjedan are altars set up by people a long time ago to offer goods to Heaven. In old records such as the Samguksagi (History of the Three Kingdoms), there are records that "The Silla Kingdom organized rituals in Taebaeksan Mountain, which it considered as a Bugak Mountain (Northern Mountain, one of the mountains for rituals)." This shows that Taebaeksan Mountain was considered to be a holy mountain in the past. Cheonjedan, or the altar, is situated at the summit of Taebaeksan Mountain. With Cheonwangdan altar in the center, there is the Janggundan Altar in the north and a smaller altar in the south. The altars are built by stacking stones, a sign of a sacred ground. The Cheonwangdan altar is made of natural stone. It has an oval shape and measures 27.5 meters in circumference, 3 meters tall, 7.76 meters wide, and 8.26 meters from front to back. The natural stone is a sort of gneiss, with the upper stone being round and the bottom stone rectangular. Such a form is based on the philosophy of Cheonwon Jibang. In the valleys nearby, there are small or large stacked stone pagodas and stone platforms, which were used for prayers. It is forbidden to kill wild animals or break off tree branches in the area.