The Naze Tower is a tall brick column raised to its present height in 1796 as a daymark and lighthouse, helping vessels fix their position along this featureless stretch of Essex coast. It was pressed into military service during the Napoleonic Wars and again in the First World War, both times as a naval signal station. In the Second World War the Royal Air Force built a Chain Home Low radar station on the Naze to track German warships and low-flying aircraft, and in 1942 extended the installation to incorporate the old tower itself. The relevant records sit in the WO, AVIA 7, and AIR 26 series at the National Archives in Kew - a paper trail of a brick tower repurposed across two centuries of British conflict.

Birds use the Naze as a waypoint. The peninsula sits on a migration route important enough that birdwatchers time visits to it, scope cases swinging from their shoulders. The marshes of Hamford Water just behind the town add another layer to the spectacle: wintering ducks rest there in numbers, and brent geese - those small, dark-bellied travellers that breed in the Russian Arctic - arrive each autumn to graze the saltmarsh. A small nature reserve protects part of the Naze itself. On any given migration day in spring or autumn, the headland fills with people standing very still, looking through binoculars at something the rest of us would miss.

The cliffs at the Naze are made of soft London Clay topped with a sandier layer, and the North Sea attacks both. Roughly two metres of cliff disappears each year. The Naze Protection Society was formed to campaign for sea defences. Schools across the region bring pupils here for fieldwork on coastal erosion - the Naze has become a kind of outdoor classroom for British geography teaching, with each generation of students measuring how much closer the tower has come to the brink. In 2010 a rock armour revetment was built directly in front of the tower, which has stopped the cliff there from retreating. But to the north, the unprotected cliff continues to erode. If the revetment is not periodically extended, the sea will outflank it and resume its advance on the tower.

Walk the cliff path on a winter afternoon and the wind comes off the sea hard enough to make your eyes water. Below, sea wall, riprap, groynes, and a permeable groyne are stacked in defensive sequence - the modern coast as a layered engineering response to a single, patient adversary. The cliff face shows the layers too: London Clay at the bottom, the Red Crag above, fossil-rich and beloved of amateur palaeontologists who comb the beach after each storm for shark teeth and ancient shells. Above all of it stands the tower, still on its high point, still doing its centuries-long work of marking the place. How long it can hold that ground is a question with a published rate of answer.