About this place

The famous hexagonal columns, part of the Hong Kong National Geopark of China, are best exposed at the High Island Reservoir's main dam. These columns formed out of volcanic ash in the caldera of a super volcano, which slowly cooled down. During this process earth movements caused the bending of the columns and allowed the intrusion of dykes.

During construction of the High Island Reservoir, particularly around the Main Dam, excavation of overlying rock and soil has exposed these rock formations beautifully.