A Cotswold dry-stone wall, built 400 years ago, is a haven for wildlife. The cracks, crevices and man-made crags of a Cotswold dry-stone wall form one of the harshest places for wildlife to live. There are plants that survive deluge and drought, 'wall-fish' that swim in a bed of slime, and royal households that each year rise to power, decline and die. There are creatures that emerge from the ghostly skins of their former selves, woody stems that keep demons from the door, and lichens, with a calendar spanning the four centuries etched into their patterns, that turn the stone wall into an enchanted wilderness; in all, a remarkable place and probably the most overlooked nature reserve in the world.