Gwangseokdae features the biggest colonnades in Mudeungsan. Standing 30 ~ 40 m high and as wide as 9 m, the massive size of the colonnades is unparalleled in the world. About 100 gigantic columns stretch for 80 m around Gyubongam. The rocks are composed of Mudeungsan tuff. Gwangseokdae is located about 800 m southeast from the summit of Mudeungsan. At about 950 m above sea level, colonnades of the Gwangseok columns are about 200 m lower than the Seoseokdae colonnades and about 100 m lower than the Ipseokdae colonnades. A small Buddhist temple, Gyubongam, stands surrounded by the rock formations. The name, Gyubong, derieved from the three stone-pillars found at the entrance of the temple. The pillars are also known as Samjonseok.