The Jeongok-ri Prehistoric Site is the prime site on the Korean peninsula for the study of Paleolithic relics, and was unearthed after the discovery of a stone implement by an American soldier who was visiting an amusement park near Hantangang River in the winter of 1978. It was identified as an Acheulean Paleolithic stone implement by an expert, and gained the attention of paleontologists from around the world. The Jeongok-ri Prehistoric Site is situated on a basalt deposit that was likely formed during the Precambrian era. With the discovery of soil wedge and tephra indicating the top layer to be estimated at least 20,000 years old, the region is also considered highly valuable among geologists.