Seven days in the Dolomites: a coral reef pushed three thousand metres into the air

Arrive, park, and spend the afternoon at valley level. Bolzano's old town is small: a couple of arcaded streets, two squares and a Gothic cathedral with a green and yellow tiled roof.

The arcades are the thing to notice. Merchants using the Brenner road built houses here that are narrow at the front and very deep, because frontage on the main street was taxed, with covered walkways on both sides so business could go on in any weather.

The old market square still has a daily fruit and vegetable market on it, which is where to buy speck, mountain cheese and apples for tomorrow's walk.

In 1991 two walkers found a body in the ice at three thousand two hundred metres, just inside the Italian border. He turned out to be five thousand three hundred years old, with his coat, his shoes, his copper axe and the contents of his last meal intact, and an arrowhead in his shoulder that killed him. He is in a cold cell at minus six degrees in a museum here, visible through a small window.

Give it a whole morning. The objects are as good as the body: a grass cloak, a birch bark container that carried embers, arrows he had not finished making.

In the afternoon walk half an hour up the river to a castle whose owners had the entire interior painted in the 1390s with the romances they liked reading: Tristan and Isolde, Arthur's knights, hunting, dancing and bathing. It is the largest surviving cycle of non-religious medieval painting anywhere.

Take a cable car in the morning. The one to the Renon plateau leaves from beside the station, climbs a thousand metres in twelve minutes, and connects at the top to a narrow gauge railway that runs across high meadows to a set of eroded earth pyramids, each with a boulder balanced on top holding the column beneath it in place. It all runs on an ordinary transport ticket.

In the afternoon drive twenty minutes to a ruined castle at the mouth of the valley that Reinhold Messner, the first man to climb Everest without bottled oxygen, bought and turned into a museum about mountains.

It is not an equipment display. It is about why people go up, what they believe about mountains, and what happens to them there, threaded through a ruin with the peaks on the horizon.

A hundred and ten kilometres, three passes, and it deserves the whole day. The road climbs east out of Bolzano, over the first pass with a lake at the bottom of a sheer rock face, then up through the Fassa valley to the Pordoi pass at two thousand two hundred metres, where the road turns into a set of stacked hairpins and the Sella massif rises straight out of the tarmac.

The detour worth making is south of the road to the foot of the highest mountain in the range, where a glacier hangs off the north face above a reservoir. It is visibly smaller than the photographs on the information boards, which is the most eloquent thing about it.

Then the last pass and down into Cortina in the late afternoon. Walk the main street once, eat, and sleep at twelve hundred metres.

The three towers are the image of the Dolomites and the walk round them is the best day here. A toll road climbs to a refuge at twenty-three hundred metres, and from the car park a broad path contours round the base of the peaks in a loop of about ten kilometres with a modest amount of climbing.

It takes three to four hours at a walking pace, with two mountain huts on the way to stop at. The north faces, which you do not see from the car park, are the vertical ones, and they come into view suddenly about an hour in.

Go early. The toll road fills by nine in August and the car park closes when it is full, and the afternoon thunderstorms in summer are not to be argued with.

The front line between Italy and Austria-Hungary ran straight through these peaks from 1915 to 1917, at altitudes where the snow killed more men than the shooting did. Both sides dug into the rock, tunnelled under each other's positions and blew the tops off mountains.

A chairlift from the pass road takes you up to a group of five rock towers where the Italian trenches have been restored as an open-air museum: dugouts, gun positions, a command post, all at well over two thousand metres with the whole range behind them. It is free, it is a walk of about an hour round the site, and it is the most affecting thing in the Dolomites.

In the afternoon a lift runs straight from the middle of Cortina to a ridge above the town, and there is a cemetery on the road south where nearly ten thousand men are buried.

One small museum before you leave, which retrospectively explains the whole week. A local collector spent his life picking fossils out of these mountains, and the result is a room of corals, shells and sea creatures gathered at two thousand metres.

That is what the rock is. Every peak you have walked under this week was a reef in a warm shallow sea about two hundred and forty million years ago, and the fossils are lying about on the scree if you know what to look for.

Then down. Venice airport is a little over two hours by the valley road and the motorway, and the descent out of the mountains is the reverse of the arrival, which is a good way to finish.