Leonardo da Vinci’s military vehicle with a conical roof is called the armored vehicle.
Leonardo designed the vehicle around 1487–1489, probably while seeking military patronage in Milan. Its circular body was covered by a conical protective shell resembling a tortoise shell. The design included cannons arranged around the perimeter and was intended to move across a battlefield while shielding soldiers inside.
The vehicle was supposed to be propelled by people turning internal cranks connected to the wheels. Some versions of the drawing contain a gear arrangement that appears to make the vehicle unable to move, leading to debate about whether this was an error, a deliberate flaw, or an intentional safeguard in a document that might be seen by rivals.
It was never built or used in battle by Leonardo. Modern reconstructions show the general idea, but they also reveal practical problems involving weight, steering, visibility, and power.