3 July 2025 The Future is the Product of the Past

Ground-penetrating radars reveal hidden passages, described in Leonardo’s drawings

As part of a PhD thesis, an innovative technological investigation conducted by the Politecnico di Milano, in collaboration with the Sforza Castle and with the technical support of Codevintec, revealed numerous hidden passages under the Sforza Castle. These structures hint at secret passageways depicted in the drawings of renowned artist and engineer Leonardo da Vinci.

As a symbol of Italian history, the castle has long captivated the attention of historians, engineers, and architects. Since its construction in the 15th century, it has functioned as a fortress, residence, and seat of power in Milan.

According to researchers from the Politecnico di Milano (Polytechnic University of Milan), some of the tunnels were probably used by the military, while another that was formerly connected to a nearby church was used by a grieving duke to sneak into his wife’s grave.

Numerous legends have been created over the years regarding its underground chambers. In one of these stories, Ludovico il Moro, Duke of Milan, is said to have visited his wife, Beatrice d’Este, through a secret passageway. Renowned polymath Leonardo da Vinci’s drawings also featured the underground passage.

The duke is said to have never fully recovered from the loss—entering, in the words of the historian Luciano Chiappini, “an almost maddening mourning” (involving the deification of his wife, around which he created something of a cult) that is suspected to have contributed to his downfall a few years later.

Geophysical surveys are undertaken at Milan's Sforza Castle. The buried passageways were found within the castle's outer wall. Credit:  Politecnico di Milano
Geophysical surveys are undertaken at Milan’s Sforza Castle. The buried passageways were found within the castle’s outer wall. Credit: Politecnico di Milano

This passage, immortalized in Leonardo’s drawings, now, thanks to technology, it seems that its existence can be confirmed. But there are numerous secret walkways.

Now, a study applying advanced ground-penetrating radar technology provides fresh evidence that such underground corridors and similar architectural features may indeed exist beneath the castle.

The investigation used advanced technologies, including ground penetrating radars and laser scanners, to accurately map and document the Castle’s subsurface and its underground structures. These instruments made it possible to reveal cavities and underground walkways at a depth of a few decimeters.

“The aim is to create a digital twin of the Sforza Castle,” said Franco Guzzetti, a geomatics professor at the university, in a statement.

This, he added, will be a model “that not only shows the current appearance of the castle, but also allows us to explore the past by revealing ancient structures that are no longer visible.”

The information gathered has not only provided historical documentation but also created new prospects for the Castle’s tourism development. Visitors would be able to explore underground spaces and inaccessible historical locations through the use of augmented reality technologies and the development of virtual pathways, providing an immersive experience that blends innovation and history.

 Politecnico di Milano

Cover Image Credit: Wikipedia Commons CC BY-SA 4.0

Related Articles

Great Wall Castle Remains Found in China’s Shaanxi

8 June 2021

8 June 2021

The remains of a Great Wall castle dating back to the Ming Dynasty (1368-1644) were discovered in northwest China’s Shaanxi...

Large Roman Complex found in Swiss Gravel Quarry

30 August 2023

30 August 2023

Archaeologists have discovered the remains of walls of a Roman building complex built nearly 2,000 years ago in the Äbnetwald...

Vikings arrived in Newfoundland 1,000 years ago: Scientists

20 October 2021

20 October 2021

Vikings’ first permanent settlement in North America – the coastal outpost in Newfoundland known as L’Anse aux Meadows now has...

Oregon may be home to oldest human occupied site in North America

12 July 2023

12 July 2023

Where and when the first humans appeared in North America is a contentious issue that many disagree on, and this...

Christians Supplied Medieval Pagans with Horses for Sacrifice for Funeral Rituals

20 May 2024

20 May 2024

In the late medieval period, pagans in the Baltic region of northern Europe imported horses from neighboring Christian nations for...

Archaeologists found 5 unique sculptures representing the Kakatiya art style in Siddipet

19 July 2021

19 July 2021

13th-century statues were found near a temple tank in the Siddipet district in the northern province of Telangana, India. On...

Oldest US firearm unearthed in Arizona, a 500-year-old bronze cannon linked to Coronado expedition

27 November 2024

27 November 2024

Independent researchers in Arizona have unearthed a bronze cannon linked to the 16th-century expedition of Francisco Vázquez de Coronado, and...

Slavic settlement and burial ground with two unusual graves discovered in Saxony-Anhalt

7 August 2024

7 August 2024

Archaeologists from the State Office for Monument Preservation and Archaeology (LDA) of Saxony-Anhalt have uncovered a wealth of medieval treasures,...

Human history in one click: Database with 2,400 prehistoric sites

10 August 2023

10 August 2023

The role of culture in human spread: Digital data collection contains 150 years of research. Human history in one click:...

Medieval ship found off the west coast of Sweden

5 February 2022

5 February 2022

A previously undiscovered wreck has been found outside of Fjällbacka on the Swedish west coast. Analysis of wood samples shows...

Malaysian rock art found to depict Ruling class and Indigenous tribes conflict

23 August 2023

23 August 2023

Researchers discovered that two anthropomorphic figures of indigenous warriors were created amid geopolitical tensions with the ruling class and other...

The Life of the Maya Ambassador Found in El Palmar was not Easy

18 March 2021

18 March 2021

El Palmar is a small plaza compound in Mexico near the borders of Belize and Guatemala. Archaeologists Kenichiro Tsukamoto and...

Madagascar’s Enigmatic Rock-Cut Architecture may have been of Zoroastrian origin

13 September 2024

13 September 2024

An international team of researchers found an enigmatic rock-cut architecture at Teniky, a site in the remote Isalo Massif in...

Bone workshop and oil lamp shop unearthed in Aizanoi ancient city in western Turkey

13 November 2021

13 November 2021

Archaeologists have unearthed a bone workshop and an oil lamp shop in an Aizanoi ancient city in the Çavdarhisar district...

Remains of a Roman stylobate found in Montenegro

19 July 2023

19 July 2023

In ancient Rhizon (Risan) in Montenegro, remains of a Roman stylobate (a shared base for multiple columns) were uncovered. In...