00:00Researchers have recently revealed secret passages designed by Leonardo da Vinci under a medieval Italian castle.
00:07By relying on a 15th century sketch attributed to the illustrious maestro of the Renaissance,
00:12a team of scientists from the University of Milan, associated with Codd-Vantech and the Sforza castle,
00:19has revealed an architectural wonder so far unexplored.
00:23The building of the Sforza castle began in 1358,
00:27but it was destroyed nearly a century later during a tumultuous succession.
00:31In 1450, Francesco Sforza, Duke of Milan, began his reconstruction on the ruins of the old fortress.
00:38Upon his death, his son Ludovico continued the embellishment,
00:41appealing to the greatest artists of his time, including Leonardo da Vinci, to whom the frescoes were entrusted.
00:47Leonardo's paintings, still visible today in the Axis room, testify to his passage to the castle.
00:53During this period, he also recorded several underground passages hidden under the exterior wall.
01:00One of his sketches, dated between 1487 and 1486, was found at the Institut de France.
01:07Of remarkable precision, it attests not only to Leonardo's profound interest in military architecture,
01:13but also to his talent for documenting existing structures.
01:18The archives attest that Ludovico Sforza dug an underground passage
01:22leading directly to the Santa Maria del Grazi basilica, where his wife Beatrice d'Este rested.
01:29Their marriage, celebrated in 1491, was happy but tragically cut short when Beatrice died in labor in 1497.
01:39Overwhelmed by this loss, the Duke isolated himself for weeks,
01:42leaving his beard grown and no longer wearing black clothes as a sign of mourning.
01:47The secret tunnel, which was 800 meters long, allowed him to hide from the gaze.
01:53It could also have been used for evacuation in case of siege.
01:56For centuries, the existence of these underground passages remained one of the many mysteries of the Renaissance,
02:02no formal evidence confirming their presence.
02:06Scientists have finally raised the veil on this long-remained secret story.
02:10Thanks to a combination of ground penetration and laser scanning radars,
02:14they were able to reconstruct an extremely precise 3D model of the structures buried under the castle.
02:20They thus identified the tunnels mentioned by Leonardo da Vinci in his sketches,
02:25which may only have been a fragment of a vast underground network still unknown.
02:30Their ambition is to develop an integral digital copy of the castle,
02:34allowing to visualize not only the preserved constructions, but also those that have disappeared over time.
02:40They also intend to integrate augmented reality into virtual travel,
02:44in order to offer visitors an unprecedented immersion in the secret passages designed by Leonardo da Vinci.
02:50It remains uncertain that Leonardo directly contributed to the construction of the recently unveiled undergrounds,
02:56but his inventive genius is undoubted.
02:59In 1502, long before the era of photography and satellites, he designed one of the most precise maps of his time.
03:06At that time, Cesar Borgia, son of Pope Alexander VI,
03:10called on him to make a remarkably detailed map of the city of Imola, located near Bologna.
03:16Until then, mapping lacked precision, lacking reliable methods, to transcribe distances at a reduced scale.
03:24Rather than developing truly practical maps,
03:27cartographers spent considerable time illuminating them with motifs such as dragons, roses, majestic castles, and all kinds of embellishments.
03:36These representations were more like pictorial works than real navigation instruments.
03:42However, Cesar Borgia was looking for a truly functional tool, and Leonardo then revolutionized mapping.
03:49If we compare Imola's satellite images to his plan today, the resemblance is striking.
03:54He faithfully transcribed each alley, each curve of the roads, and even the exact dimensions of the buildings.
04:00And he accomplished this feat entirely by hand, using only a pencil, a ruler, a compass, and a few of his own inventions.
04:08In order to collect all the necessary data, he wandered the streets for weeks,
04:13carrying a odometer, a large wheel that rotated according to his movements, and measured the distance traveled by means of a cable.
04:20He also relied on a magnetic compass to accurately determine the directions.
04:25He also developed an instrument called the compass, designed to measure angles within a circle.
04:32Thanks to this tool, he was able to precisely analyze the orientation of the streets,
04:37the size of the intersections, and the distance separating the dwellings from the main axes.
04:42Once inside, he relied on his notes and calculations to draw a map on a scale of remarkable precision.
04:50In his works, Leonardo also used a technique developed by the Florentine humanist Leon Battista Alberti.
04:57The latter had developed a method that allowed him to inscribe an entire city in a circle using polar coordinates.
05:04Eight straight lines converging to a single center represented the main directions of a compass.
05:10Leonardo applied this system to the cartography of Imola, dividing the city into eight sections and naming no building, even the most insignificant,
05:18which made his map one of the most advanced of his time.
05:21The illustrious inventor nourished an ambitious dream, to design a machine allowing man to fly.
05:28He carefully observed the birds, bats, and flying deer in order to understand their movement in the air,
05:33then he drew a flying machine, the ornithopter.
05:37According to him, by imitating these natural movements, humans could rise to the skies.
05:42His prototype evoked the appearance of a bat, with two large wings stretched out to a width exceeding 10 meters.
05:49To guarantee the balance between resistance and lightness, he envisaged making the armor out of pine wood and covering it with raw silk.
05:57The pilot of the machine had to lie flat on a wooden plank located in its center.
06:02The activation of the wings required a pedal linked to a system of rods and pulleys, while an additional crank allowed to increase the power.
06:12An aerodynamic helmet also served to ensure the control of the aircraft.
06:17By synchronizing the movements of his hands and feet, the pilot could make the wings beat and rotate, like a flying bird.
06:25However, a major obstacle remained.
06:28Human strength was not enough to generate the necessary lift when taking off.
06:32If the machine had been able to operate once at an altitude, it was impossible for a single individual to raise it from the ground.
06:39Léonard was probably aware of this, but his concept nevertheless influenced the design of the flying machines imagined a few centuries later.
06:47Léonard de Vinci was ahead of his time with many of his inventions, but his concept of a humanoid machine was distinguished by its visionary character.
06:55Under the patronage of the Sforza family, known in particular for the construction of the old tunnels,
07:01he imagined a mechanical knight capable of moving his arms, pivoting his head, and even opening and closing his mouth.
07:08His mastery of the anatomy and mechanisms of body movement allowed him to design this unique machine.
07:14Its operation relied on an external cable system, operated by a crank and completed by a set of internal gears.
07:23About 450 years later, in the 1950s, the sketches detailed by Vinci's mechanical knight were rediscovered.
07:31Researchers then attempted to recreate this robot from original drawings.
07:36In 2002, a roboticist named Mark Rothsheim, who had worked for NASA and Lockheed Martin,
07:42was inspired by his old notes to design a functional model of Vinci's mechanical knight.
07:47Another project designed by Léonard for the Sforza Duke was an innovative bridge, thought to be removable and easily transportable.
07:54Destined for troops in the countryside, having to cross rivers and dunes, this bridge was designed to pivot above water and land on the other bank.
08:04It was equipped with wheels and an ingenious system of ropes and pulleys, allowing it to be mounted and folded just as quickly.
08:11To ensure stability, it was designed to add a specific counterweight.
08:15In his notes, Léonard described his bridge as light but solid, and designed several variants for the Duke.
08:22Among his other creations was a model of ultra-fast-assembly bridge, designed to allow troops to cross several streams of water successively.
08:31While scientists continue to explore the secret passages imagined by Léonard de Vinci, new aspects of human history emerge.
08:39Who knows what other architectural wonders are still to be discovered?
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