"Hong Kong trail section 7 with Obelisk Hill sidetrack loop + D’Aguilar Peak Start : Tai Tam Reservoir North bus stop - take #14 bus from near Sai Wan Ho MTR Finish : Shek O beach - take #9 bus home to Shau Kei Wan MTR Follow the flat HK trail to marker post H075 where a bridge crosses the catchwater and a ribboned trail goes north up Obelisk Hill. From here an anti-clockwise circuit back to H075 takes a little over 1hr. The actual summit of Obelisk Hill is a fenced off GPS station. 200m prior stands one of two concrete obelisks built ~1900 by the navy. The second obelisk can be spied away to the south on the shore by Red Hill. Ships moored in the natural shelter of Tai Tam Bay used the obelisks to calibrate, aka “swing”, their compasses; the obelisks lie on the same line of longitude, so by lining up on them sailors could accurately define true north. A secondary use for the obelisks may have been to navigate obstacles on approach to Tai Tam Harbour. Descend NW to regain the HK trail at marker post H071. Soon after the summit are some WWII defence buildings to explore; an old fibreglass helmet liner lay on a window ledge, what era I don’t know. Continue on the HK..." — davidb • Mar 26, 2020