Found at 39.2635131, 20.6196193

Location – Greek mainland in Epirus, near Parga, roughly opposite the southern end of Corfu, in what looks to be a former volcanic crater.

Ok, smartarse, what is that?

It looks very much like a small livestock watering installation: a circular water reservoir/trough with a concrete apron and an access road built specifically to reach it. The green centre appears to be standing water.

Combined with the surrounding rough, apparently grazed land, that makes sheep or goat grazing considerably more plausible. It may be communal or municipal grazing infrastructure rather than part of a conventional fenced farm.