The Pokfulam Conduit
In early Hong Kong, you got your water from wells or streams. The first attempt to provide a more reliable source was the Pokfulam Reservoir, and its associated conduit. The conduit carried water round the island from the reservoir, following the hillside above Pokfulam Road, and ending near the junction of Albany Road and Robinson Road.
There are still plenty of signs of this old water system. Pokfulam reservoir is the most obvious, clear to anyone looking south from the Peak:
And the path of the old conduit above mid-levels is immortalised by the name of the road that was built on top of it:
Thomas, one of the regular contributors to Gwulo, has been using the 'Places' feature to document other parts of the conduit's route that are still visible. Here they are on a map and list. (If you know of any more, just create a Place and give it the tag Pokfulam Conduit, and it will automatically appear on the map and list below.)