Representing Busan, Oryukdo Islets have been designated Cultural Property Scenic Spot No. 24. According to an old literature Dongraebuji Sancheonjo published in 1740, the Oryukdo Islets were located east of Julyoungdo Island. The literature added that the looks of peaks and hills are strange, standing side by side in the sea, so the number of the peaks can be 6, if seen from the east, or 5, if seen from the west. This is what the islets’name comes from (O means five and ryuk means six). The islets belong to Busan Bay in Yongho-dong, Nam-gu, Busan. The order of them from the land from the closest to the furthest is Woosakdo (32m above the sea level), Suri (33m), Songgot (37m), Gul (68m) and Deungdae (28m). The closest Woosakdo has a one meter wide sea cave. The Oryukdo Islets were born from the sedimentation of andesitic breccia, andesite, tuff, tuffaceous sediments products of the volcanic activity in Yucheon Group 80-70 million years ago. A six km thick layer of extrusive igneous rocks and sedimentary rocks in the upper part of the islets has been worn away by the process of denudation from the Mesozoic to the Cenozoic and to date. *denudation: wearing away of the Earth’s surface by weathering followed by flattening of the surface by the transported weathered materials One hundred twenty thousand years ago, these islands were connected as a single ridge. However, having been eroded by sea waves along the fracture zone developed inside rocks over a long time, the ridge was broken into several parts. After 3 times of uplifts, the separated parts were developed into the forms of marine terraces, i.e., rock islands with wave-cut terraces. Today’s Oryukdo Islets were formed by repeated occurrences of wave erosion which had resulted in sea caves and wave-cut platforms all over the places. All but the island with a lighthouse are uninhabited.