Fan Bay Deep Shelter and Sound Mirrors, Kent

Carved 70 feet into the White Cliffs of Dover, Fan Bay Deep Shelter was excavated between 1940 and 1941 to protect the gunners manning the three 6-inch coastal defense guns above. Descend 125 original concrete and steel steps into a network of arched, corrugated-iron-lined tunnels that once housed up to 200 troops. The shelter’s damp, chalk-hewn corridors still echo with the footsteps of soldiers who lived, slept and prepared for enemy bombardment just 20 miles from occupied France.

Guided tours illuminate stark personal quarters, stores and ventilation plant rooms where a pioneering fan and heater system battled the chill and condensation.

Alongside these World War II relics, visitors encounter vestiges of an earlier conflict: two First World War sound mirrors cut into the cliff face. The northern 15-ft dish (circa 1917) and a larger 20-ft sibling (circa 1920) once concentrated the roar of incoming aircraft into stethoscope-fed collectors, acting as mechanical precursors to radar. Exposed and stabilized in 2014, these rugged concrete “listening ears” stand sentinel above the deep shelter, linking two eras of Britain’s coastal defense.

The Fan Bay Mirrors are part of the “South Coast Sound Mirrors”. Spanning roughly 1916 to 1936, the South Coast Sound Mirrors form a series of interwar “listening ears” scattered along England’s southern shore. Built from curved concrete with focal-point collectors, they acted as early aircraft detectors—radar’s mechanical forerunners—designed to pick up the roar of approaching enemy planes.

Today, six key sites preserving seven of these historic acoustic dishes remain open for exploration: Abbot’s Cliff (Langdon Cliffs), Kent. Denge Sound Mirrors, Kent. Fan Bay Sound Mirrors, Kent. Warden Point Sound Mirror, Isle of Sheppey, Kent. Joss Gap Sound Mirror, Kent. Hythe Sound Mirror, Kent. Selsey Sound Mirror, West Sussex.

The Fan Bay Sound Mirrors form part of the White Cliffs of Dover NT property. Park at Fan Bay Deep Shelter car park and follow the cliff-top trail to the mirrors.

Photo credit: Disco-Dan