Thanks Tiompan...yes it was Maes Howe....don't know where I got the idea it was long dismantled.....and yes I agree it might not have been a deliberate design...just sheer good luck...noticed only on one certain day from one certain position and significance attached from that day onwards...which was why I wondered if anyone had filmed evidence of the "roll" sunrise/set on other days from different viewpoints(at Silbury) as they have at other places...like MH. To be deliberate would surely take a long observation period...made longer depending on weather conditions. So ANY construct could have the same effect on any day depending on where you were standing...which got me to my original question about a vewing point/marker being erected at the same time as the hill was built to indicate the siting and rolls were less than coincidence....it seems as though such a marker was only a later addition then.....cleared up..Cheers.