Nine days from Lake Como to Lake Maggiore: the part of Switzerland that speaks Italian

Como's cathedral took nearly four centuries to finish, which is why the front is late Gothic, the sides are Renaissance and the dome on top is eighteenth century baroque by the architect who was busy at the same time in Turin. Its oddest feature is on the west front: seated statues of Pliny the Elder and Pliny the Younger, both born in this town, both unrepentantly pagan, sitting either side of the main door of a Catholic cathedral. No other church in Italy does that.

Walk down to the water afterwards. The lakefront is a broad promenade with the ferry pier in the middle, mountains dropping straight into the water on both sides, and seaplanes taking off from the far end of it, because Como has had a flying club on the lake since the 1930s.

At the western end stands a small round neoclassical temple built in 1927 for Alessandro Volta, who was born here in 1745 and stacked zinc and copper discs into the first battery in 1800. His instruments are inside, a lot of them the actual objects, and the volt is named after him. It takes twenty minutes and it is the best twenty minutes in town.

The funicular has climbed the wall behind the town since 1894, and it takes seven minutes to lift you from the lakeshore to the village of Brunate on the ridge. From the top, a level street of belle epoque villas runs along the crest, and a marked path carries on for half an hour to a stone lighthouse built in 1927 in Volta's honour, with a spiral staircase inside and the whole lake below.

You can walk back down to Como in about an hour on a stepped mule track through the woods, which is steep, shaded and much more pleasant than it sounds. Or take the funicular again and save your knees.

Spend the afternoon on the water at the western edge of town. Villa Olmo is a neoclassical palace built for a Como family and now owned by the city, with formal gardens open free to the public and rooms that open for exhibitions. Next door is the lido, a lakeside pool complex with a diving board and a stretch of open water roped off, which is where the town swims all summer.

Start at Sant'Abbondio, ten minutes out on the western side of town,, which is much older and much plainer than the cathedral: a Romanesque basilica consecrated in 1095, with five aisles, two bell towers and almost no decoration except in the apse, where a medieval fresco cycle covers the whole curve of the wall. It is usually empty and the light in it is remarkable.

Then get on a boat and stay on it. The public service runs up the western arm from the pier in the middle of Como, stopping at every village on both shores, and it is the only sensible way to understand the shape of this lake: two arms meeting at a promontory, walls of rock, and villa after villa built by people who wanted to be looked at from the water.

The slow boat takes about two hours to reach the middle of the lake, where Bellagio sits on the point and Varenna faces it across the water. Get off at either, have a long lunch and walk the stepped lanes, then come back on an afternoon sailing. The great gardens at Tremezzo and Lenno are further stops on the same line if you would rather spend the day in one of them.

The train from Como San Giovanni crosses the frontier at Chiasso and reaches Lugano in about forty minutes. Nothing changes except the price of coffee. The signs, the newspapers and the conversation on the platform stay Italian, because Ticino has been a Swiss canton since 1803 and has never spoken anything else.

Lugano's old centre is small, arcaded and gathered on one wide square of ochre facades with the town hall on one side and enough cafe tables to seat the canton. The cathedral is up the hill towards the station, with a Renaissance front from 1517 stuck onto a much older building and a terrace looking down over the roofs.

The reason to come, though, is a plain church by the lake at the western end of the promenade. Santa Maria degli Angioli holds a Crucifixion painted across the entire dividing wall by Bernardino Luini in 1529: hundreds of figures, three crosses, a city behind them, and a scale nothing else in Switzerland matches. It costs nothing and most people walk past the door.

Take the boat or the local train two stops to Paradiso and get the funicular, which has climbed the rock of San Salvatore since 1890. The summit is a bare dome at 912 metres with a small church on it, and the view is the reason people put up with the queue: the whole bay of Lugano below, the lake bending away in three directions, and on a clear day the Monte Rosa massif on the horizon.

Behind the summit the ridge runs south into the Collina d'Oro, and you can walk down that way in about ninety minutes to Montagnola, which is where the second half of the day is.

Hermann Hesse came to Montagnola in 1919 with nothing, rented four rooms in a mock-baroque villa, and spent the next forty three years here writing Siddhartha, Steppenwolf and The Glass Bead Game. He died in the village in 1962 and is buried below it. The museum in the tower house he lived in keeps his glasses, his typewriter, his watercolours and his straw hat, and the signed walk around the hill follows the paths he took every day.

The other funicular starts at Cassarate on the eastern side of the bay and climbs to Monte Bre at 925 metres, which claims to be the sunniest mountain in Switzerland and has the paperwork to argue about it. The old village just below the top is a knot of stone houses with a scattering of sculpture and art through its lanes, and the terrace faces west across the whole lake.

From there the walk is downhill all the way. A path drops off the mountain through terraced olive groves to the shore, then follows the water east as the Olive Trail, with panels explaining how a crop everyone associates with the south has been grown on this bank since the Middle Ages. It takes about an hour and a half from the top and is easy going, though there are steps.

It ends at Gandria, which is pressed against the mountainside above the water with no road into it, only stairways between the houses and a landing stage below. There are two or three terraces hanging over the lake and the boat back to Lugano takes half an hour. Do it in that order, walking out and sailing home, and it is the best day of the trip.

The train runs north up the valley to Bellinzona and then turns west, taking about fifty minutes in all with the change. The landscape opens out as you go: the lake gives way to a river plain between mountain walls, vineyards on the terraces, and the light gets brighter, because Locarno sits at the head of Lake Maggiore and is the warmest place in the country.

Piazza Grande is the centre of everything, a long rectangle of arcades on one side and open ground on the other. For two weeks every August it fills with eight thousand chairs facing the largest open air screen in Europe for the film festival, which has been running since 1946 and hands out a golden leopard rather than a palm or a bear. For the rest of the year it is a market square with cafes under the arches.

Behind it the old town climbs in lanes to the Visconti castle, a fifteenth century fortress cut down to a quarter of its size by the Swiss and now holding the town museum, whose best room is a collection of Roman glass dug out of the local graves. The conference that produced the Locarno treaties met in this town in October 1925, and the settlement it reached held for about ten years.

Twenty minutes back down the line is the town that controlled the way north to the passes for five hundred years, and the defences it built to do it are the reason it is on the UNESCO list. Three castles stand in a line up the hillside, joined by walls, with a fourth fortification thrown right across the valley floor to block it.

Start at Castelgrande on the rock in the middle of town, the oldest and largest of the three, reached by a lift cut up through the rock from a square below. Its two towers, its long wall running down the hill and its museum of the frescoes taken off a demolished house are a good hour and a half.

Then walk the wall to Montebello, the prettiest of the three, built in the thirteenth century on a spur above the town with a moat and a drawbridge and a courtyard you can sit in. If you still have legs, a path climbs another twenty minutes to Sasso Corbaro at 462 metres, which was thrown up in six months in 1479 after the Swiss lost a battle and expected another one. The view from its terrace takes in all three castles, the town and the valley they were built to close.

A funicular leaves from behind the station and climbs the cliff face in a few minutes to Orselina, where a sanctuary hangs off the rock above the town. It was founded in 1480 after a Franciscan brother said he had seen the Virgin on this ledge, and it grew into a church, a monastery and a covered stairway of chapels zigzagging down the cliff.

Inside there is a Ciseri of Christ carried to the tomb and a Flight into Egypt by Bramantino, and outside there is a terrace with the whole of the top of Lake Maggiore under it, the river delta, and the Italian shore in the distance. Come back on foot rather than riding, twenty minutes on the stepped path through the chapels, which puts you in the old town for a last coffee.