‘I didn’t understand the Mendips until I began to explore them from below,’ Sean says. ‘Almost everything here involves the underworld somehow: quarrying, mining, caving. Bronze Age lead mining. Coal mining by the Romans. Quarries for limestone grit, so big they have a spiral ramp cut to a narrow core, in order that the lorries can get up and down, like an industrial version of Dante’s descent in The Inferno. And basalt quarries to supply hardcore for top-dressing roads.’
