This is precise measured and positioned red paving stones rectangle, that you can see on any sattelite image. For example: https://www.bing.com/maps?cp=45.255109%7E19.844861&lvl=20.3&style=a

You can align sattelite image using it. Current Bing offset: 3.20; -4.10. In JSOM you can use Imagery Offset Database plugin.