1 Natural hexagonal columns
Built in the 1970s to help alleviate water shortages when mainland China cut off water supplies to the city due to the 1967 Hong Kong riots, the High Island Reservoir sits in Sai Kung and is part of the Hong Kong UNESCO Geopark. Its two main dams, West Dam and East Dam, lie about an hour’s journey apart—which should give you an idea of the reservoir’s size—but it's the farther East Dam that is home to some geological wonders.
Aside from the Insta-friendly dolosse wall with geometric, jack-shaped blocks of concrete, East Dam is most well-known for its hexagonal rock columns, formed naturally 140 million years ago in a volcanic eruption. Such rock formations exist elsewhere in Hong Kong, but High Island Reservoir is the only place where you can actually get to touch them.
East Dam is reachable by taxi, but we find the best way to get there is to hike in from Pak Tam Chung via Section 1 of the MacLehose Trail, which brings you to West Dam before arriving at East Dam. Follow the High Island Geo Trail at the base of the dam to observe the columns at close range, including some S-shaped ones which have been warped by earthquakes while still in the process of solidifying, before ending at a sea cave. We’re sure you’ll agree after seeing it all in person that this corner of Hong Kong is pretty dam interesting.
The entire hike is also a fairly easy one without any sharp inclines, suitable for beginners. From East Dam, you can even choose to make your way further to Po Pin Chau or Long Ke Wan, both only short hikes away. Here is a detailed guide to hiking to High Island Reservoir.