Mont-Saint-Michel audio guide,
five stops, free.

Stand far enough back that the whole thing fits, and it looks like a single building. It is not. What you are looking at is a granite rock about 960 metres round, with a village wrapped around its foot, a wall wrapped around the village, and an abbey wrapped around the summit, each layer resting on the one below.

The rock came first, by about 525 million years. It is leucogranite, magma that cooled underground, and it outlasted the softer stone around it when the sea came in, which is why it stands alone in the bay. People called it Mont Tombe. Then, the story goes, in 708 the archangel Michael appeared three times in a dream to Aubert, bishop of Avranches, and asked for a sanctuary out here. The legend adds that he left the mark of his finger on the bishop's skull, and a skull with just such a scar is still shown in the basilica of Saint-Gervais in Avranches.

Read the Mont from the bottom up and you are reading the Middle Ages' idea of order. At the foot, outside the walls, the fishermen and the farmers. Above them, stores and houses. Above those, the great halls. And at the very top, God, the abbey and the monks. Benedictines arrived in 966, installed by Duke Richard the First of Normandy, and in the eleventh century their builders did something outrageous: they built four crypts around the tip of the rock and set an abbey church 80 metres long on top of them.

Look to the right of the tower, at the thicket of pinnacles and flying buttresses. That is the choir, and it is not the first one. The Romanesque choir collapsed in 1421, and it was rebuilt afterwards in Flamboyant Gothic.

The Hundred Years' War explains the wall in front of you. From 1417 Abbot Robert Jollivet closed the whole lower town inside a continuous crenellated rampart, and you go in through three gates: the Porte de l'Avancée, the Porte du Boulevard, and the Porte du Roy, where the Grande Rue begins. The English laid siege from 1423 and never got in. In the assault of the seventeenth of June 1434 they left two wrought-iron bombards behind on the sand, and the Montois brought them inside as trophies and called them the Michelettes.

Now the top. The spire is younger than it looks. Victor Petitgrand rebuilt the bell tower and raised this neo-Gothic spire between 1892 and 1897, and it is what gives the Mont the pyramid outline everyone draws. The gilded figure on the point is Saint Michael himself, by the sculptor Emmanuel Frémiet, and he has been up there since 1897.

Out of the stairs and onto open stone, with the whole bay spread in front of you. This terrace is where the abbey finally lets you see where you are, and it is also a scar.

You are standing on the church. This paving was the original forecourt of the abbey church, plus the first three bays of its nave. After a fire in 1776 those bays were taken down, and the flat classical façade behind you, finished in 1784, closed off what was left. Its foundations went down through Notre-Dame-sous-Terre, the small pre-Romanesque church hidden under your feet, and split it in two. It had been swallowed by later building and forgotten, until Paul Gout found it in 1898, digging under the church floor.

Now the view, and give it time, because it changes while you watch. To the west, the Rock of Cancale and the coast of Brittany; to the east, the cliffs of Normandy. Two granite massifs break the flat: Mont-Dol inland to the west, and out in the bay to the north, the islet of Tombelaine. In good weather you can pick out the Chausey islands, and they are not idle scenery. The granite this abbey is built from came from Chausey. The whole bay covers nearly 500 square kilometres. The dead-straight fields to the west are polders, land won from the bay and now used for market gardening, and the salt-meadow sheep graze below you where the sea comes and goes. Seals and dolphins are regulars out there.

Then turn round and look straight up. This bell tower has burned so often it is almost a tradition: storms and lightning set the abbey on fire a dozen times. In 1794 the top of the tower carried a Chappe optical telegraph, one link in the line between Paris and Brest. What you see now is Victor Petitgrand's work of 1892 to 1897, a neo-Romanesque tower and a neo-Gothic spire 40 metres tall.

On the point is Saint Michael, by Emmanuel Frémiet: plates of rolled, beaten and gilded copper, 3.5 metres tall and 800 kilograms, put up in pieces on the sixth of August 1897. He was restored in 1987 and regilded in 2016, and in March 2016 a helicopter lifted him clean off the spire so that his lightning conductor could be repaired. From this terrace, with nothing but sky behind him, he is the last thing the whole Mont points at.

The abbey is behind you now, and so is the climb. You came out through the northern gardens, under the north front of the Merveille, the wall with the tall, narrow windows that Victor Hugo called the most beautiful wall in the world, and down onto the ramparts. This round platform is the Tour du Nord, and it is the best free seat on the Mont for the one thing here that never stops moving, which is the sea.

The tower belongs to the first town wall. It was begun in the middle of the thirteenth century, and around 1311 Abbot Guillaume du Château completed a rampart that ran from here to the east end of the parish church of Saint-Pierre; three years later the Mont had its first garrison: one man-at-arms and five servants. Look at the parapet. It is blind, with no openings in its face, and it stands out on machicolations, gaps in the overhang through which the defenders could drop whatever came to hand. The walk beyond, with its seven towers running down to the Tour du Roy by the gate, has its parapets from the fifteenth century, when the English were just across the water.

Just across the water is not a figure of speech. Look north, and the low granite hump 3 kilometres out is Tombelaine. During the Hundred Years' War the English turned it into a stronghold, and ruins from that time are still on it. Today it is a bird reserve, where many birds nest in spring.

Now the flats. The difference between high and low water here is roughly 14 metres, and on the big tides around the spring and autumn equinoxes the sea can pull back as far as 15 kilometres, then return very fast, until it surrounds the rock completely. The wave at the front of it is the tidal bore. The legend says it comes in at the speed of a galloping horse. In fact it averages about 6 kilometres an hour, a brisk walking pace, and the abbey itself strongly advises nobody to go out into the bay alone. Medieval pilgrims had a name for this place, Saint Michael in peril of the sea, and they meant it.

The same sands kept people in. From the Revolution until 1863 the abbey above you was a prison, the Bastille of the Seas, and some 14,000 prisoners passed through it. Nobody needed a higher wall to hold them. The tide and the quicksand did that, and they are still out there, shining, between you and the shore.