SH5659 : Vandalism I
And dykes fall down without any help.
Once walking in the Howgill Fells in Westmorland, a section of wall collapsed nearby, without contact. It was raining heavily at the time, and the foundations just chose that moment to lose to gravity.
It is also worth remembering that thousands of people were out on the hills of Wales, every weekend, long before they coloured the OS maps orange.