When I visited England circa 1990, there was an annoying fence around Stonehenge. Most of the time when I see coverage of the famed megalithic site, the fence is still there. However, when watching a recent special called Ghosts of Stonehenge there were tons of aerial shots where there wasn't signs of fenceposts, much less the fence! The fence did reappear in a few far-off shots where it was way in the background, so obviously it is still there. So my question is: do they sometimes take the fence entirely down for events or just for filming of overhead shots? If they do so, how to they not leave signs of where the fence once was? Or do they CGI it away?