Even today, getting to the Channel Island of Sark is an adventure, involving a 55-minute journey by sea from Guernsey, and then a climb from the quay through a tunnel in the rock to reach the top of the sheer cliffs that surround the island on all sides. Given the challenges of getting to Sark, the island provides the perfect opportunity to study connectivity and isolation down the ages – one of Sir Barry Cunliffe’s perennial preoccupations, sparking his excavations there. Who came here, when, and why? And what does it tell us about the mobility of past visitors? Chris Catling reports.