I was just wondering if anyone knew what the two semi-circular marks that are revealed in dry weather on the Alexandra Recreation Ground were caused by. There's one on each side. I've noticed one of them in previous years, but the one on the Newlands Park side appeared this year for the first time. Suggestions so far have been for bandstand or cricket pavilion, but in that case, why two of them? I don't think they are pitch markings as the colour change in the dry weather would indicate some sort of foundations underneath. I wondered if they might have been anti aircraft gun emplacements, but I saw a 1945 aerial view and there's no sign of anything.
Here's a picture of one of them - as you can see there seem to be 2 semicircles joined by an odd shape between them.http://www.newsshopper.co.uk/news/10552735.Pictures__Have_aliens_landed_in_Sydenham_park_/#gallery1