Royan and Cordouan: The Lighthouse at Sea and the Concrete Church

Required Activities

• Take the boat from Royan to Cordouan between April and October, cross to the lighthouse by flat-bottomed launch at low tide, and climb the 301 steps to the top

• On the first floor find the King's Apartment, fitted out by Colbert in 1664 with a real fireplace, grey Sainte-Anne and black Belgian marble and pilasters monogrammed for Louis XIV and Queen Marie-Thérèse — no king ever slept in it. On the floor above, the chapel is the only consecrated chapel in any lighthouse in the world, and weddings and baptisms are still held in it

• Go into Notre-Dame de Royan and find how it is held up: alternating V-shaped prestressed concrete ribs of the Laffaille system with 500 square metres of Henri Martin-Granel's glass between them, under a saddle-shaped hyperbolic-paraboloid roof. Then look for what the sea air has done to concrete poured fast and cheap in 1955, and read the inscription on the second bell, cast for the victims of 5 January 1945

• In the Grottes du Régulus at Meschers, cut into 25 to 30 metres of white cliff, work out the order the chambers were used in — grain store, smugglers' hide, Protestant refuge when their worship was banned, housing for the destitute, then a dance hall — and ask why they are called Régulus: a French 74-gun ship scuttled in the estuary below in 1814 to keep her from the British

• Walk the grid of Talmont, laid out on Edward I's orders in 1284 with the streets crossing at right angles for defence, and notice how deliberately low the limewashed houses are built to take the wind out of the estuary gales; then go up to Sainte-Radegonde on the cliff edge and find where the church stops short — a storm brought down a slice of cliff and took part of the building with it