Italy week begins under the Rialto Bridge: the wooden crossings that kept falling, the twelve thousand short piles under its stone arch, why Venice meets all six of UNESCO's cultural criteria, and why the city doesn't really stand on stilts.
Venice sits in a lagoon at the northern end of the Adriatic Sea, in the Veneto region of northeast Italy. A narrow barrier island shields the lagoon from storm waves, and the tide moves in and out through three inlets, at the Lido, Malamocco and Chioggia. The city is spread over about 118 small islands and laced with canals. The protected area takes in the whole lagoon, from Torcello in the north to Chioggia in the south.
The first lasting settlements in the lagoon date from the fifth century, when people from the mainland took refuge from raids on its sandy islands, and over time those refuges became permanent. Around 810, under Doge Agnello Partecipazio, the lagoon's government moved from Malamocco to the Rialto islands. Around Rialto the scattered settlements grew together into one city, which UNESCO's record describes as tiny islands joined into a single urban system, with the canals as its arteries.
Venice became a sea power and Europe's link with Asia. Its merchant galleys sailed to the markets of the Islamic Near East and came home loaded, and the city became Christian Europe's most important point of contact with the Muslim civilisations of the Near East. Marco Polo, who travelled to China and back in the thirteenth century, was a Venetian. Rialto was the centre of all this commerce and finance.
The bridge that kept falling
Until the nineteenth century only one bridge crossed the wide Grand Canal, and it stood at Rialto. The first crossing there floated on boats. By the late twelfth century there was a bridge called the Ponte della Moneta, the coin bridge, and in the thirteenth century a new wooden bridge replaced it, with a middle section that could be raised to let tall ships through. In 1310 it burned during a failed coup. In 1444 it collapsed under a crowd gathered for the wedding procession of the bride of the Marquis of Ferrara. Each time, Venice rebuilt it in wood.
Vittore Carpaccio painted that wooden bridge in the mid-1490s, in a canvas for the Scuola Grande di San Giovanni Evangelista, a confraternity. The bridge rises in the background while gondolas crowd the canal, and one of the gondoliers in the foreground is a Black man. The painting now hangs in the Accademia gallery in Venice.
In 1524 the bridge collapsed again, and Venice resolved to build in stone. For decades designs came in and none was agreed. Planners had to weigh room for boats underneath against shops on top. Andrea Palladio proposed three arches, which would have blocked the larger boats; his design was not chosen. In 1588 the Senate settled on a single stone arch carrying two rows of shops and three walkways. Antonio da Ponte, an elderly Venetian builder who had worked on the Doge's Palace after the fire of 1574, was put in charge, with his nephew Antonio Contin working alongside him. A rival architect, Vincenzo Scamozzi, predicted the bridge would fall. Da Ponte built it to his own plan, starting with the foundations.
What holds it up
The soil at Rialto is soft, laid down by water, and several metres below it lies a stiffer clay called caranto. Under each end of the bridge are about 6,000 wooden piles, some 12,000 in all, each about three and a half metres long and typically around fifteen centimetres across. They were driven in by heavy rams and packed close together. Da Ponte did not set them on one flat level: he arranged them in three steps, one below another. Timber planking went on top.
Venetian builders kept layered foundations like this, two or three layers of planks, for the load-bearing walls of important buildings. Such decks sit two or three metres below the surface, where they stay wet, and the wet keeps wood-rotting fungi away.
The stone bridge was finished by 1591, and Scamozzi's prediction did not come true. It outlived the republic that built it, which ended in 1797 when Napoleon Bonaparte's soldiers entered Venice. Until the mid-nineteenth century it stayed the only bridge across the Grand Canal; anywhere else, people crossed by gondola ferry, the traghetto.
Why it is on the list
Venice was inscribed in 1987 and meets all six of UNESCO's cultural criteria. The record calls it a unique artistic achievement, with one of the highest concentrations of masterpieces in the world. Its painters, from Bellini and Giorgione to Titian, Tintoretto, Veronese and Tiepolo, completely changed how space, light and colour were seen. It bears witness to a civilisation linking East and West, Islam and Christianity, and its buildings form a complete range of medieval architecture, from Piazza San Marco to modest homes on narrow streets. UNESCO also names the city as a symbol of a people's struggle to master a hostile nature.
Not quite on stilts
It is easy to picture Venice raised on long poles above the water. The engineering studies describe something closer to the ground. Under a typical Venetian building the piles are short, often one to three metres, set close together and hidden beneath timber decks two or three metres down, with stone and brick walls on top. The Rialto Bridge is no exception.
Our week in Italy begins under a bridge. In 1588, to carry a single stone arch over the Grand Canal in Venice, builders drove about six thousand wooden piles into the soft ground beneath each end of the Rialto Bridge.
This is Ours to Keep. I'm Mira, and today: Venice and its Lagoon. I'm an AI voice; the facts come from official records and checked sources.
Islands in the lagoon
Venice sits in a lagoon at the top of the Adriatic Sea, in the Veneto region of northeast Italy. A narrow barrier island shields the lagoon from storm waves, and the tide comes and goes through three openings to the sea, at the Lido, Malamocco and Chioggia. The city itself is spread over a hundred and eighteen small islands, laced with canals. The protected area is far bigger than the city. It takes in the whole lagoon, from the island of Torcello in the north to the town of Chioggia in the south.
Until the nineteenth century, only one bridge crossed the wide Grand Canal. It stood at a place called Rialto.
The first lasting settlements in the lagoon came in the fifth century. People from the mainland took refuge from raids on its sandy islands. Over time, those temporary refuges became permanent. For a while, the lagoon's government sat on the island of Malamocco. Then, around the year 810, under Doge Agnello Partecipazio, it moved to the cluster of islands at Rialto. In 828, two Venetian merchants took the relics of Saint Mark out of Alexandria, in Egypt, and brought them home to Venice.
At the head of the state stood a doge, its highest official, who held office for life. Over the centuries, councils hemmed in his powers, until the doge could no longer govern on his own.
Around those islands, the scattered settlements grew together into one city. UNESCO's record describes a group of tiny islands joined into a single urban system, with the canals as its arteries.
Venice grew into a power at sea. Its ships made it Europe's link for trade with Asia, and it became Christian Europe's most important point of contact with the Muslim civilisations of the Near East. Its merchant galleys sailed to the markets of those lands and came home loaded. In the tenth and eleventh centuries, Byzantine emperors granted Venetian merchants special trading privileges in their empire. Marco Polo, the merchant who travelled to China and back in the thirteenth century, was a Venetian.
Rialto was the centre of its commerce and finance. In 1514, a fire swept through the Rialto market, and the market was rebuilt. To reach Rialto from the other bank of the Grand Canal, people needed the bridge.
The bridge that kept falling
The first crossing at Rialto floated on boats. By the late twelfth century there was a bridge here, known as the Ponte della Moneta, the coin bridge. In the thirteenth century a new wooden bridge took its place. Its middle section could be raised, to let tall ships through.
That wooden bridge had a hard life. In 1310 it burned during a failed coup. In 1444 it collapsed under a crowd that had gathered to watch the wedding procession of the bride of the Marquis of Ferrara. Each time, Venice rebuilt it in wood.
A painting shows what the old bridge looked like. In the mid-1490s, the painter Vittore Carpaccio put it into a canvas for one of the city's confraternities, the Scuola Grande di San Giovanni Evangelista. It belongs to a series of paintings about the confraternity's relic of the Cross. This canvas shows a miracle at Rialto. The wooden bridge rises in the background, and gondolas crowd the canal below it. In the foreground, one of the gondoliers is a Black man. The painting now hangs in the Accademia gallery in Venice.
In 1524 the bridge collapsed once more, and Venice resolved to build in stone. That proved slow. For decades designs came in, and none was agreed. The planners had to weigh room for boats underneath against shops on top. One of them, by Andrea Palladio, had three arches. It was not chosen, and three arches would have blocked the larger boats on the canal. Designs are also recorded from Jacopo Sansovino and Giacomo Vignola.
In 1588 the Senate settled on a single stone arch. It wanted two rows of shops on top, and three walkways. The man put in charge was Antonio da Ponte, an elderly Venetian builder who had worked on the Doge's Palace after a fire in 1574. His nephew, Antonio Contin, worked alongside him. A rival architect, Vincenzo Scamozzi, predicted that da Ponte's bridge would fall. Da Ponte built it to his own plan anyway, starting with the foundations.
Up close
So let's look at that bridge from the top down. On its broad deck stand two rows of shops, as the Senate asked. Three walkways run between and beside them, one down the middle and one along each outer edge. The shops sit in two arcades, under arches. Beneath them, the whole thing crosses the canal in one stone arch. That single arch leaves room for taller boats, gondolas among them, to pass underneath.
Now go down, below the water line and into the ground. The soil at Rialto is soft, laid down over time by water. Several metres further down lies a stiffer layer of clay, which Venetians call caranto. Da Ponte designed his own foundations for this ground. Venetian builders used a handful of timbers for foundations, with larch, pine and elm among them.
Under each end of the bridge, about six thousand wooden piles were driven in. That makes some twelve thousand in all. Each pile is short, about three and a half metres long, and most are around fifteen centimetres across. Piles like these were driven in by the blows of heavy rams, and they stand packed close together. Da Ponte did not cut them off at one flat level. He set the piles in three steps, one level below another.
On top of the piles went timber planking. In Venice, builders kept this kind of layered foundation for the load-bearing walls of important buildings, and the deck was two or three layers of planks thick. Such decks sit two or three metres below the surface. There they stay wet all the time, and that keeps the fungi that rot timber away from the wood. Above the planks, Venetian builders usually set the first courses of masonry in blocks of Istrian stone, and the walls rose from that stone base.
By 1591, the stone Rialto Bridge was finished, and Scamozzi's prediction never came true. The bridge outlived the republic that built it. That republic ended in 1797, when Napoleon Bonaparte's soldiers entered Venice and the last doge, Ludovico Manin, left office. Until the middle of the nineteenth century, the Rialto Bridge stayed the only bridge across the Grand Canal. Anyone crossing anywhere else took a gondola ferry, called a traghetto.
Why it's on the list
So why is it on the list? Venice meets all six of UNESCO's cultural criteria. The record calls the city a unique artistic achievement, with one of the highest concentrations of masterpieces in the world. Its influence travelled through its trading stations, from the Dalmatian coast to Asia Minor and Egypt, and shaped architecture there. Its painters, from Bellini and Giorgione to Titian and Tiepolo, changed how Europe saw space, light and colour. UNESCO calls Venice a witness to a civilisation that linked East and West, Islam and Christianity. Its buildings make up a complete range of medieval architecture, from the great monuments of St Mark's Square to modest houses on small streets and squares, all adapted to a difficult site. The lagoon counts in its own right, as an outstanding wetland habitat, mudflats and fishing villages included. And Venice stands for people mastering a hostile nature, and for the merchants and explorers, Marco Polo among them, who set out from it. Venice and its Lagoon was inscribed on the World Heritage List in 1987.
The surprise
It is easy to picture Venice standing on tall wooden stilts, like a pier over open water. The engineering studies describe something quite different. Under a typical Venetian building, the piles are short, often between one and three metres long, and set close together in the ground. They are hidden beneath timber decks, two or three metres under the pavement, and the stone and brick of the walls rise from those decks. The Rialto Bridge is no exception: its piles are only about three and a half metres long.
Tomorrow, from wood kept in the water to wood in the fire: in Naples, pizza makers learn their craft by watching the masters at work, and bake in wood-fired ovens.
