The whole of Venice, the "Floating City", is an engineering and architectural wonder of the world.
The entirety of both the city of Venice and the Venetian Lagoon have been declared by UNESCO, the United Nations cultural organisation, a World Heritage Site.
This is how the Unesco website introduces this city of "Outstanding Universal Value":
"Founded in the 5th century and spread over 118 small islands, Venice became a major maritime power in the 10th century. The whole city is an extraordinary architectural masterpiece in which even the smallest building contains works by some of the world's greatest artists such as Giorgione, Titian, Tintoretto, Veronese and others."
The uniqueness of Venice
Every year Venice repeats the ceremony of her marriage to the Sea. The sea is what Venice depends on and at the same time is threatened by.
A city like Venice, with its exceptional – indeed unique – beauty, gives the impression of being a miracle. Too good, or in this case too beautiful, to be true. In fact, even if it's not literally a miracle, there have been quasi-miraculous circumstances that have kept Venice alive and afloat.
To understand this we must start from the beginning, from the time when a group of people inhabiting the undefended hinterland and countryside near the Lagoon in the Veneto region of Italy were fleeing the barbarians invading Italy from the north and the east after the fall of the Western Roman Empire, in search of a safe haven where to build their homes.
Venice is practically unique in northern Italy as a major urban centre that doesn't appear to have Roman roots, although we have indications that the lagoon was continually inhabited from Roman times onwards.
The first archaelogical evidence... Venice is not mentioned in any classical text, Roman historians did not name it, and there are almost no surviving early documents or historical records on the foundation of Venice. So archaelogical evidence is the only source to work on.
For a long time, specifically until the mid-1980s, there has been very little archaelogical information about Venice and its history, uniquely among major historical European cities. Only in the last three decades, as archaeological and palaeoenvironmental studies have taken place in association with building restoration work, we have started to get a clearer picture of the origins of Venice, although some aspects still remain shrouded in mystery.
The real historians of the beginning of Venice were not writers but the builders and architects that have left us physical clues.
Until the end of the 3rd century AD, whenever an ancient source uses the name "Venetia", it refers to to the broad geographical region corresponding to the modern Veneto, and not a town or even the Lagoon area. The written Venetian chronicles started only much later, in the 11th century.
Although the Venetian Lagoon had long been inhabited and other historical accounts (or legends) exist, the foundation of Venice as a city is traditionally considered to have taken place at noon on the Feast of the Annunciation of the Archangel Gabriel to the Blessed Virgin Mary, 25 March, in 421 AD, when Venice's oldest church, San Giacomo di Rialto, was consecrated.
The creation of Venice
As explained in the article on the Venetian Lagoon on this site, such an environment was one of the most unsuitable to build a city on. Venice was erected not on a solid foundation but on weak marshlands near a collection of 118 small muddy islands, the same ones that are today separtaed by many canals and connected by many bridges.
Venice was built here exactly and paradoxically for that very reason, as the same habitat that rendered life difficult for the city's inhabitants was also inaccessible and arduous for its would-be invaders and enemies. The first people from the mainland who gave origin to this incredible urban marvel were at the time escaping from the hordes of barbarians from Northern and Eastern Europe, descending on Italy after the collapse of the Western Roman Empire, raping and pillaging. Local populations either suffered or ran away.
The Veneti, the inhabitants of towns and villages along the Lagoon, found refuge on the islands and saved themselves from invasion. Despite the shallowness of the waters, the islets were impossible to reach by foot, and the raiders often had no ships. And anyway only the locals knew where the channels deep enough for seafaring vessels were located.
This gave Venice the safety on which she built her empire of the sea, with dominance of the Eastern Mediterranean in shipping and commerce that made her one of the wealthies and most powerful cities in Europe.
But les't go back to the fascinating beginnings, not unlike those of the Europeans who settled in the American continent. The refugee settlements were originally meant to be temporary, but over time became permanent and required a solid construction technique adapted to the unique environment.
The buildings in Venice were not constructed directly on the islands. The marsh islands were subject to regular flooding, and dry land suitable for building was rare. Right from the beginning the inhabitants of the floating city had to change the current habitat conditions to meet human needs. Therefore, since the earliest Venice settlers had only water to build on, their first job was to build their own strong foundations for the edifiices.
This they did by driving millions of thin, sharpened wooden poles underwater through the mud, sand, clay and into the seabed of the Lagoon, then by placing oak planks on top of these poles, and by placing several thick layers of marble or Istrian limestone on top of the planks: these were to be the foundations of Venetian buildings, and from that point up the construction was generally done in the usual way, with wood or brick.
Marble was chosen for its high resistance to water.
Botanical remains of timber from constructions have revealed that the early builders of Venice carefully selected different types of wood for particular purposes. So, the vertical poles were overwhelmingly of alder, while the horizontal planking was of elm or oak. All three species withstand well repeated wetting and drying, hence their choice. Each wooden pole, or stake, measured about 4 metres.
The secret of the longevity of Venice's wooden foundations is the fact that, being underwater, they are not exposed to oxygen, which is required by many bacteria and fungi responsible for the decay of wood. Furthermore, the effect of salt water around and through the wood petrifies the timber over time, so that it gets hardened and stone-like.
Most of these wooden poles are still intact. The Venetians' ingenuity, hard work and determination has protected them from the forces of nature, but only up to a point. This city built ultimately on water could not be as safe as one built on land. Over the centuries, the weight of the buildings has driven the poles deeper into the seabed.
In fact, one could ask the question: why has Venice not sunk further or more quickly?
A recent Italian study has shown that some of La Serenissima’s largest buildings use as a firm foundation "caranto", a special local stone that developed in northern Italy during the Glacial Maximum around 18,000 years ago, as materials eroded from the Alps washed down and sedimented on the plains. Caranto calcified during the the warm climate of the early post-glacial period, becoming highly compressed and very strong, ideal for supporting building foundations.
Over time the water would submerge the ground or first floors of Venice buildings, then as now.
Photo credit: Beautiful Water Street Venice. Source: BigStockPhoto