Octagons, circles, triangles and a six pointed star

This 40 metre mast was erected in 1998 to commemorate  the former site of the Admiralty's (Semaphore) Signalling Station, at Mt Wise.

It is easy to see why this site was chosen for signalling to Royal navy ships, because from this point there is a commanding view down over the River Tamar and out to Plymouth Sound, and all the ships would pass beneath it on their way to and from the Royal Naval Dockyard.