[2020 Update: Marker position updated with correct coordinates from H Lo.]
Position of the marker is approximate, but it is on the path from the redoubt down to the hairpin bend in the road. The path is shown clearly on the OSM map. <Read more ...>
"The U-shape disused tunnel is reckoned to be used for shipment of ammunition during the war time and might have been abandoned or filled up after the war time." according to govt study this year. Says CEDD doesn't have further details. Map included in the Heritage Impact Assessment for new pumping station. http://www.amo.gov.hk/form/HIA_Report_Cotton%20Tree_%20Drive_%20FWPS.pdf
