Mont-Saint-Michel

The granite mass rises from tidal flats that stretch to the horizon, the abbey at its peak catching light long before the sand does. Mont-Saint-Michel stands where Normandy meets Brittany on France's Channel coast, an island when the tide fills the bay and a sentinel when it drains — and here, at the highest tides in continental Europe, the sea pulls back fifteen kilometres from the coast and comes in again fast enough to catch the unwary.

The first sanctuary on the summit was consecrated in 709, built by Bishop Aubert of Avranches at the request, the story goes, of the Archangel Michael himself. Over the centuries that followed the monks raised a Romanesque church and then, at the start of the thirteenth century, the Gothic Merveille — three storeys of refectory and cloister hanging off the north face of the rock — and the mount became one of the major pilgrimages of Christendom alongside Rome, Santiago and Jerusalem. It has since been a fortress and a prison, and it was among the first sites inscribed by UNESCO. A footbridge has replaced the old causeway so that the sea can circle the rock again; the medieval village that spirals up to the abbey is free to walk all year, while the abbey itself is ticketed. The bay's tidal range reaches fifteen metres, and guides lead walks across the sands all year round — the only way anyone should be out on them, because the channels shift and the water returns faster than it looks.