Inside the Grigna there are tunnels. Iron ore was quarried from the flanks of these valleys, in Valsassina and Valvarrone, where the earliest traces of mining go back to Roman times, and along the Gerenzone stream, which flows down into the city through the districts of Laorca, Malavedo, Rancio and San Giovanni, the water turned the wheels of dozens of forges and wire-drawing mills.

Out of them came nails and iron wire, chains, buckles, farm tools. The woods supplied charcoal for the furnaces, the streams the driving force, Milan a day's journey away the market. Lecco was the city of iron, and the paths that today lead to mountain huts were once the roads of those who went up to quarry. Then the workers began climbing those same mountains on Sundays, for free, for nothing, and since they knew how to work metal, they built their own gear.

Keep that sentence in mind, because it explains Lecco better than anything else. But let's set it aside for a moment, because there's a city to explore first.

Lecco sits at the southern tip of the eastern branch of Lake Como, wedged between rock and water within 45 square kilometers that hold a provincial capital of nearly 47,000 inhabitants and fifteen named districts. It's the only point where the lake flows out: here the Adda river resumes its course southward, which makes Lecco a threshold rather than a shore.

Above the city rise the majestic peaks of the Grigne and the Resegone; inside it, a medieval and neoclassical historic center, the settings of The Betrothed, and two twentieth-century stories worth the trip on their own.

The center can be toured on foot in a couple of hours, and it's all centered around Piazza XX Settembre and the lakefront.

The tallest landmark is the Basilica of San Nicolò, dedicated to the patron saint of sailors and boatmen, rebuilt in neoclassical style by Giuseppe Bovara between 1831 and 1862. But what you see from every corner of the city is the bell tower: neo-Gothic, built between 1882 and 1904, 96 meters tall, among the ten tallest in Italy and the second tallest in Lombardy after the Torrazzo of Cremona.

Locals call it il Matitone ("the Big Pencil"), and you only need to look at it against the light to understand why. It stands on a tower of the Visconti castle, has a base 21 meters in diameter that narrows to ten where the octagon begins, and its bells together weigh ninety-six quintals — the same number as its height in meters, purely by coincidence.

On the guided tour you climb almost four hundred steps up to a balcony above the bells, and from up there the view sweeps the full horizon.

A little further on is the Azzone Visconti bridge, which locals simply call the Ponte Vecchio (Old Bridge) ever since the Kennedy bridge arrived in 1955. Built between 1336 and 1338, 131 meters long and nine wide, today with eleven arches: it was once fortified, with towers, drawbridges and its own castellan, since the border with Venice ran through here. The towers were torn down in 1799, during the campaign against the French. From the parapet you can see the Isola Viscontea below and, to the north, the crown of the Alps opening up ahead.

On the square stands the Visconti Tower, the keep of the fourteenth-century castle and the only piece of the fortifications to survive: restored in 1816 by the same Bovara, long used as a prison, a city museum since 1932 and today home to exhibitions. Next to it, the Palazzo delle Paure, in neo-medieval style, dating from 1916, once home to the Chamber of Commerce, now houses the contemporary art section of the civic museums. Its name, which sounds like something out of a Gothic tale, comes far more prosaically from the taxes once paid there.

The lakefront promenade closes the loop, with views opening toward Malgrate and Monte Barro, and the golden statue of San Nicolò watching over the city from the water. The patron saint is celebrated on December 6, and Lecco's children still get an apple that day.

Those who come for the novel find more than they expect, as long as they know where to look, and knowing that Manzoni describes the lake from above and from afar, through the eyes of a Milanese aristocrat, while the city beneath that gaze was busy making nails.

Villa Manzoni at Caleotto is the eighteenth-century house where the writer spent his childhood and adolescence, and which he sold in 1818. Today it's the Manzoni museum and home to the civic museums, with a picture gallery and rooms dedicated to the novel: a must for anyone visiting with The Betrothed in mind.

But the place that truly makes the trip worthwhile is Pescarenico, the fishermen's district on the Adda. It's the oldest and best-preserved part of the city, and above all, it's one of the very few places Manzoni actually names, rather than inventing or disguising it. You can reach it on foot from the Ponte Vecchio, and it still has the narrow courtyards and low-rise layout of lakeside villages. The Capuchin convent of Fra Cristoforo once stood here; the church of Santi Materno e Lucia is what remains of it.

On the Zucco headland, meanwhile, once stood the palace of the Arrigoni family, the Manzonis' historic rivals, which tradition identifies as the house of Don Rodrigo. It was demolished in 1937 to build a rationalist villa in its place — a detail that says quite a lot about how this country treats its own legends.

Now let's pick up the thread from the beginning, because here's the story no guidebook tells.

In 1926 a seventeen-year-old boy gets off the train in Lecco. His name is Riccardo Cassin, he comes from San Vito al Tagliamento, he lost his father at age four in a work accident in Canada, and he's been a blacksmith since he was twelve. In Lecco there's work in iron, and he knows how to work it.

He starts out in boxing. Then, in 1929, he puts together a climbing group with friends from the San Giovanni district, one of the wire-mill districts on the Gerenzone, and heads off to climb the spires of the Grigna. Within ten years, that blacksmith from Friuli becomes the strongest mountaineer in Europe: 1935, the north face of Cima Ovest di Lavaredo; 1937, the northeast face of Pizzo Badile; 1938, the Walker Spur on the Grandes Jorasses, three days on the wall, tackled having seen that face only in a postcard. During the war he commands the Gruppo Rocciatori della Grigna, the core of the Lecco Resistance.

In 1946, on a path climbing from Laorca to the Piani Resinelli, a group of young men decide to join forces to do what none of them could do alone. The Ragni della Grignetta are born: the Ragni di Lecco ("Spiders of Lecco").

The sweater is red and bears a seven-legged spider on the left sleeve; the name comes from the nickname of one of the founders, Gigi Vitali, whom Tita Piaz had called "the Spider" for the way he moved on rock.

From there the story leaves the lake and travels the world. 1958: Gasherbrum IV, an expedition led by Cassin, with Carlo Mauri and Walter Bonatti reaching the summit. 1961: the south face of McKinley, never climbed before; Cassin is fifty-two. And then, on January 13, 1974, the day Lecco still tells the story of: Casimiro Ferrari, Mario Conti, Pino Negri and Daniele Chiappa appear on top of Cerro Torre via the west face, after two months of siege and thirty-seven rope lengths.

The expedition was celebrating the hundredth anniversary of the Lecco section of the CAI (Italian Alpine Club). The city took it so personally that ever since, that granite spire planted at the far end of Patagonia has been treated by the people of Lecco much like a pillar of the Grigne themselves.

Cassin, meanwhile, had gone back to his old trade. From 1947 he produces rock pitons, then hammers and ice axes; in 1950 the first carabiners and the first down jackets for high altitude; by the late 1950s, the prototype of the climbing harness; in 1970 titanium crampons; in 1986 an ice axe with a carbon-fiber shaft. They're made by a small company in Premana, CAMP, owned by the Codega family, born as a blacksmith's forge in a valley of miners.

The circle closes inside a single object. That same company put into production the first ice axe with a metal shaft, and gave it a name: Cerro Torre.

Cassin died at the Piani Resinelli on August 6, 2009, seven months past his hundredth birthday. At seventy-eight he had gone back to the Badile to reclimb his own route, wearing the red sweater.

There's a second story from Lecco, and it's the same one turned upside down: instead of upward, downward.

Pietro Vassena, born in Malgrate in 1897, was a self-taught inventor with a workshop first in his home town and later in Lecco, on Via Cavour: thirty-three patents, engines, mopeds, machines of every kind. On April 28, 1945, he's arrested on the charge of having supplied his gas generators to the Germans and locked up in an elementary school converted into a prison, in cell number 3, which had been the third-grade classroom. He's released after a few days. But in that cell he had begun thinking about a submarine, and when he builds it, he calls it C3.

He builds almost all of it himself, between 1945 and 1947, with resources laughably modest compared to the laboratories of the time: there are stories of one of his wife's pots being used to house the telephone system, and a kitchen timer ending up in the controls. The launch takes place in the Canottieri Lecco boat basin. The bathyscaphe is then taken to Argegno, at the lake's deepest point.

On March 12, 1948, at 1:16 p.m., the C3 settles on the bottom at -412 meters, carrying Vassena and Nino Turati, a former submariner from Calolziocorte. To grasp the scale of it: military submarines of the time could dive to about a hundred meters. It's a world diving record, and it will stand unbroken until 1960. Vassena returns to the city and is carried on people's shoulders to the town hall.

A few weeks later, Auguste Piccard, the Swiss physicist, comes looking for him, wanting to see how the C3 was built. He'll use some of those solutions for the bathyscaphe Trieste, the one that in 1960 will reach 10,900 meters in the Mariana Trench. The C3, on the other hand, sinks in the autumn of 1948 off the coast of Naples, and it's still down there.

On the lakefront, near the Canottieri, there's a bronze face. It's him. Almost everyone walks past it without knowing that this man, starting from a small-town workshop, had gone deeper than any navy in the world.

The Grignetta (Grigna Meridionale, 2,184 m) is the training ground where half of Italian mountaineering learned its craft: a comb of spires and towers that seem custom-made for climbing, and which indeed have nicknamed routes. Above it, the Grignone reaches 2,410 m. You set off from the Piani Resinelli, where you can also visit the Anna mine, one of the many dug into these mountains until the 1950s: it's the most direct way to see with your own eyes the sentence we started with.

The Resegone, 1,875 meters at Punta Cermenati, the jagged ridge that Manzoni compared to a saw and that no one has been able to look at the same way since; it's climbed precisely from the Piani d'Erna. And you can also reach exactly that spot by cable car from Versasio, in just a few minutes: it's one of the easiest viewpoints on the whole lake, and a decision you can make the same morning just by looking at the sky from your window.

Above the Rancio district looms the Medale wall, a compact and severe rock face that's one of the historic playgrounds of Italian climbing. It's clearly visible from the state road, and many drive beneath it every day without knowing what it is.

Down at water level, finally, the Sentiero del Viandante ("Wayfarer's Path") sets off from Abbadia Lariana, the ancient route that runs up the eastern shore to Colico: you walk along the hillside above the lake, passing through villages and vineyards, and you can do it in stages, using the train to get back. In Abbadia, incidentally, there's a silk-mill museum, which is another chapter of the same story: this was a place that made things, plain and simple.

Lecco's cuisine sits exactly where the city sits, that is, between the lake and the mountains, and you eat well in both directions.

From the water come whitefish, perch, which here ends up over risotto, breaded and fried in butter, and above all missoltini, sun-dried and salt-pressed shad, served with polenta and a splash of vinegar: it's the signature dish of the Lario, not to everyone's taste, but worth trying where they know how to make it.

From the mountains comes the rest. Polenta uncia, rich with butter, garlic and melted cheese, is a dish from Valsassina, and Valsassina is also one of Lombardy's great cheese-making areas, with natural caves where cheeses age for centuries. It's worth bringing a piece home.

In one day in Lecco, spend the morning in the center — for example the Basilica of San Nicolò, the Azzone Visconti bridge, the Visconti Tower, and the Palazzo delle Paure — go down to Pescarenico for lunch, and spend the afternoon up high, at Piani d'Erna by cable car or at Piani Resinelli by car.

With half a day more, add Villa Manzoni at Caleotto and a walk along the lakefront to the Vassena monument.

One suggestion on order that's worth following: if you're short on time, go up first. Even just to Piani d'Erna, even just for half an hour. Looking at the city from above, seeing how tightly it's squeezed between rock and water and how quickly the mountains rise up around it, changes everything you see afterward. The 96-meter bell tower, the fourteenth-century bridge, and the story of a blacksmith from Friuli who arrived at seventeen looking for work all fall naturally into place.

Nearby, if you're staying: Malgrate on the other side of the bridge, Monte Barro park, Valsassina behind the Resegone, and the eastern shore toward Varenna and Bellano, all reachable by train.

Lecco is the easiest town on Lake Como to reach without a car, and almost no one takes advantage of it. The station is right in the center, a few minutes from the lakefront: from Milano Centrale or Porta Garibaldi it takes around an hour, and the line to Como, opened in 1888, covers the 41 kilometers between the two cities. From here trains also run up the eastern shore toward Varenna, Bellano and Colico. By car, it's about an hour from Milan.

The best months are April–June and September–October: the rock is in good condition, the air is clear, and the Grigne aren't too hot to climb. In summer the city is warm and you can't swim in the center, but just twenty minutes by cable car or car take you a thousand meters higher. Winter is the underrated season: days with the north wind when you can see all the way to the Alps, and the basilica, museums and neighborhoods work much better without the crowds.