Abbot’s Cliff (Langdon Cliffs), Kent Sound Mirror

The South Coast Sound Mirrors are a network of interwar acoustic “listening ears” built along England’s southern shoreline between about 1916 and 1936. Their curved concrete surfaces and focal-point sound collectors were a precursor to radar, aiming to give early warning of incoming enemy aircraft. Today six principal sites—with seven surviving mirror structures—can still be explored.

The Abbot’s Cliff (Langdon Cliffs) sound mirror is a free-standing 20-ft diameter mirror cast in July 1928 under Dr W.S. Tucker’s Thames Estuary scheme. • Access: Follow the North Downs Way from Dover’s St Margaret’s Road car park; the dish sits atop the white cliffs just east of South Foreland.

Photo credit Andrew Bone