>>912963
Somebody save these so we don't repeat (posted a couple of these in Nov) - it's NOT a tennis court, it's a tarp.
On the pic where there's no tarp, there are stakes. In one pic (sorry for bad quality, that's Google Earth's crappy 3D) it shows the tarp being held up several feet above what is presumably a tunnel opening.
The best pics of Pedo Island are Feb 5 2017 in Google Earth. I suggested several threads ago to download the app "We Maps 04" - amazing detail for this place! It's where you could see the 'face' of the sundial...