I have posted in the past about the series of Fortress Observation Posts that was built around Port Elizabeth at the start of the Second World War as harbour defences, showing in particular the one in Cape Recife. The FOP most people may have seen before is the one sitting on the hill above Schoenmakerskop. Notice the curves along the edges which was part of the design to make it blend in against the bush and hills behind it. This was done so that it wasn't easily visible from the sea. And before somebody asks where the bush and hills are, this picture was taken from the side.