Baekyangsan Mountain is 642 m above the sea level, rising on the main ridge of the Geumjeong Mountain Range, a backbone of Busan. It is located on the border between Jin-gu and Sasang-gu in Busan, extending to the Geumjeongsan Mountain in the north. The mountain reveals the general history of geological changes in Busan: various types of pyroclastic rocks as a result of volcanic ejecta from the Yucheon Group 80-70 million years ago; sedimentary rocks deposited when the volcanic activity temporarily halted; and granites that intruded into the aforesaid rocks deep down below. At its foothill is Geumjeongbong Peak (397m), a.k.a. Soemisan, made up of shale, mudstone, and limestone. The peak has well preserved lake bed sediments formed during the Cretaceous. It is also a home of Seongjigok Riverhead, a precursor of water supply of Korea and a riverhead of Busan. Around the riverhead has been developed Children’s Grand Park with thick forests of cypresses and cedars. On the hillside in the south is Sunamsa Temple which is believed to have been built by the Great Buddhist Monk Wonhyo. Moreover, a royal azalea habitat and an observatory on a mountain top provide the best views overlooking the city of Busan. A trekking course of the mountain leads to waterfalls, talus, tors, inselbergs and limestone caves formed by calcic paleosols. The connection to the Children’s Grand Park, one of main attractions of Busan, adds more fun to the trekking experience through hidden elements awakening five senses such as forest therapy and a story-telling flower trail.