Mam Tor, Castleton, Derbyshire, England

Visitors to Castleton should find it hard to miss the gashed Mam Tor. The reason for that absence of greenness is the same as that explaining why the village has only one western approach by road. Apparently, it's all down to geology with a layer of clay providing too much lubrication between a top layer of shale and the limestone bedrock on which it sits. That sort of thing causes landslips and the one closing the old A628 is among these and the resulting effect on the hillside is present for all to see. There seems not been any sort of effect on the remains of an old fort that you'll find on the summit along with a goodly number of daytrippers on a good day.