I grew up on a farm near the hills of The Burren in the west of Ireland. If you look closely, you can see walls made of stacked stones cross-crossing the hills, as if to demarcate farmland - but those hills are not arable farmland, so why? The British refused to offer free food to the starving, so they made people build these completely pointless walls to “earn” the food. They’re now known as the Famine Walls.