Sai Kung and the Hong Kong UNESCO Global Geopark

The rocks here record a violent past. Around 140 million years ago a supervolcano erupted in the area, and as the thick layers of volcanic ash and lava cooled and contracted they cracked into columns, some rising up to 100 metres. Faulting later shattered some columns into breccia and twisted others before they had fully hardened, while waves carved sea caves and stacks along the coast.

High Island was once a separate island divided from the peninsula by the Kwun Mun Channel. Following a water supply crisis in the 1960s, two large dams were built across the channel between 1969 and 1979, creating High Island Reservoir. A memorial near the East Dam remembers workers who died during construction. The area's geological value was recognised when the Hong Kong National Geopark opened in 2009; it joined the UNESCO-supported Global Geoparks Network in 2011 and is now known as the Hong Kong UNESCO Global Geopark.

City residents escape here at weekends to hike, swim, kayak and eat seafood by the harbour, and the old town still has fishing families, Hakka villages and small temples. Conservation of the geopark is taken seriously, and visitors are expected to keep to trails, leave rocks and plants undisturbed and take their litter home.