Leonardo the city planner: Da Vinci’s New Milan

‘Renaissance men’ had been dreaming about the perfect cityscape before Leonardo da Vinci. The idea of using rules and angles to create a zone of majestic order appealed to many a polymath of the time, artist and philosopher Leon Battista Alberti among them.

The city of Pienza, about 50 miles south of Florence, was built practically from scratch under the patronage of Pope Pius II between 1459 and 1462. The clean lines of its palaces and cathedral set around the main square resemble a theatre set even today.

Yet while the early architects of the Renaissance were concerned with beauty and classical order, Leonardo’s thoughts and theories for an ideal city went beyond the aesthetic.

He wanted to use his interest in hydraulic engineering to construct an ideal city that also functioned as a clean and hygienic space, with goods, people and waste moving seamlessly. His ideas, sketched in one of his notebooks, were so far-reaching that they are being studied today by futurists as a way of proofing metropolises against climate change.

That the pursuit of the ideal city was on Leonardo’s mind was already evident in his job application letter to his sponsor, the Milanese strongman Ludovico Sforza, who later became the Duke of Milan and who employed Leonardo as an organiser of pageants and theatre as well as an artist, architect and engineer.

In the application, Leonardo emphasised how he had designed light, portable and fire-resistant bridges for the battlefield, and his knowledge of hydraulics. “... in times of peace I can give perfect satisfaction and be equal of any other in architecture and the composition of buildings public and private; and in guiding water from one place to another, ” he wrote.

Leonardo was 30 when he moved to Milan in around 1482. The city he found was a crowded medieval warren of buildings, with no sanitation. Soon after the young painter had arrived, it was hit by an outbreak of the bubonic plague that killed 50,000 people - more than a third of the city’s population at the time. The Black Death, as the plague was known, came originally from China and was spread by fleas living on black rats along the Silk Road.

“With his scientific instincts, Leonardo realised that the plague was spread by unsanitary conditions and that the health of the citizens was related to the health of their city,” wrote Walter Isaacson in his 2017 biography of Leonardo.

Leonardo’s ideas and sketches for an ideal city were executed between 1487 and 1490 and were contained in what is believed to have been the first of his notebooks, ‘Paris Manuscript B’ and ‘The Codex Atlanticus’, written around the same time.

Scholars believe he had just read Alberti’s classic ‘Ten Books on Architecture (De Re Aedificatoria)’, given to him by a lighting engineer who had come to Milan from Mantua to consult for work on the lantern structure on top of Milan Cathedral that Leonardo was also working on.

His idea was to “disperse its great congregation of people which are packed like goats, one behind each other, filling every place with fetid smells and sowing seeds of pestilence and death”.

Ten new towns designed and built from scratch would be constructed on a site near a river.  

Drawing on the knowledge he had gained from studying Milan’s canals, Leonardo wanted to use water to connect the city like a circulatory system – like the one in the human body (he was also studying anatomy at this time) – to keep goods, people and waste on the move above and over ground, on land and on water.

“You will want to take a river that runs briskly, so that it will not corrupt the air of the city, and this will also be convenient to use for cleaning the city frequently, when the support below that city is lifted,” he wrote. “And with rakes and chopping, you can remove the mud that gathers in them which will mix in with the water and make it turbid. And this ought to be done once every year.”

In order to avoid floods, Leonardo positioned his city at a certain distance and connected it by means of a “larger canal” equipped with a lock: “When you close the door, the water will fill the lock and the low ships will rise and return to the general level of the city.”

The artificial canals were connected to the river by a basin, which also served to regulate the level of water.

His ideal town-planning principle was to have a multi-tiered city, which also included an underground waterway to flush away effluent.

The bottom tier was for the poor, goods and traffic – horses and carts – and ran on the same level as the canals and basins, so wagons could be easily offloaded.

Going up one more level, he envisaged porched areas with workshops and retail shops. The arched walkways were for the citizens to walk and shop freely, even on rainy days.

The shop owners and artisans would live above the shops, as was customary at the time.

Finally, on the city’s top layer, as distant as possible from freight traffic, trading and any eventual disease from below, would be the private apartments of the bourgeoisie, or “gentlemen”, as Leonardo called them. Here, you would find an independent indoor walkway designed for social gatherings and walks.

“Let only that which is good looking be seen on the upper level,” wrote Leonardo.

The roads on the top tier of his ideal city had to be as wide as the tallest house, or 20 braccia (70 metres) “and have a ½ braccio slope from the sides towards the middle”.

Homes were to have a main entrance on the top level and a tradesman’s door on the lower level. Leonardo planned to light them with airshafts and link one floor to another with a winding staircase. He specifically insisted on a winding staircase because they lacked corners, making it harder for men to urinate. He even designed a paddle wheel to clean the city streets.

In the ‘Codex Atlanticus’, Leonardo laid down his ideas for stables, which he designed to take away the usual stink: the horses would be attached with their backs towards the water, the floor sloping downwards with hatches to sling their waste into an underground river. Fodder was unloaded directly from the hay-loft on the upper level by means of a slide fashioned inside the walls. He even gave instructions to keep the shaft clean and plastered, so the hay didn’t get stuck.

Unfortunately for Leonardo, Sforza did not adopt his vision of the city, perhaps due to the enormous cost. He did, however, later employ Leonardo to sort out the plumbing and sewers of his castle.

His ideas of ‘zoning’ for cities, as laid down in his multi-tiered vision, were never really taken up either. The city sprawl of the industrial revolution did create special zones for certain activities, but there is no evidence the great Victorian engineers, such as Joseph Bazalgette, studied the Renaissance master.

“He didn’t have an immediate legacy as such because his architectural works weren’t studied for many centuries afterwards,” explains the Leonardo curator of the Milan Science Museum. 

There was, however, renewed interest in Leonardo’s ideal city when, in 1956, Alberto Mario Soldatini made a model, now housed in Milan’s Leonardo Da Vinci National Museum of Science and Technology.

Ten years later, the former Italian prime minister Silvio Berlusconi made his fortune when he embarked on a housing development of 4,000 residential apartments east of Milan. The main peculiarity of Milano Due is a system of walkways and bridges that connects the whole neighbourhood, so that it is possible to walk around without ever intersecting traffic. It was marketed as a residential neighbourhood for families of the upper-middle class with children. Could Berlusconi, or his architect, have seen the exhibition at the science museum?

Leonardo’s concepts of multi-level urbanisation are now being looked at by modern visionaries such as Devin Liddell, the chief futurist at the Seattle-based technology design company Teague, which was behind the design of both the Pringles box and the Boeing aircraft.

“The ideas are especially portable to what we are facing right now – the reshaping of cities from an old system to a new one,” says Liddell.

The new infrastructure and organisation for autonomous vehicles, for example, could take some inspiration from Leonardo. “The tiering notion is applicable to robot cars because we will have to separate them from pedestrians,” says Liddell. “Driverless vehicles will not understand human eye contact or gestures, greatly increasing the possibility of an accident.”

The city of layers envisaged by Leonardo could also take large delivery trucks off the road, maybe underground, and could be of inspiration to town planners as they grapple with the challenges of climate change.

Hurricane-prone Miami is already building new apartment blocks with a car park on the raised first and second floors to remove vehicles from the risk of flooding at street level.

“Coastal cities will have to re-engage with how they interact with water,” says Liddell. “There is inspiration in Leonardo’s hydraulic engineering for cities here as well.”