Mt. Manisan stands 472.1 meters high from sea level. Three mountain peaks stand abreast of each other viewing the beautiful scenery, and Chamseongdan altar is located on top of central peak. From top, you can see many islands in the south of west sea, and also the Mt. Song-aksan in the north on bright weather. Chamseongdan altar is known as place where Dangun performed religious services to Heaven, and like the Cheomseongdae in Gyeongju, the base of altar is round symbolizing the sky and square platform the earth.