High Island Reservoir East Dam

This guide to the High Island Reservoir East Dam in Hong Kong starts with the hexagonal rhyolite columns beneath your feet, cooled from a supervolcano some 140 million years ago. It traces how they came to be exposed: the 1967 riots that cut off the mainland water supply, and the decade-long dam-building project an Italian contractor carried out afterward, quarrying straight into the cliffs. You'll hear about the reservoir's scale and the small memorial beside the dam to the workers who didn't live to see it finished. Lean over the rail near the spillway for the clearest view of the columns.