What armored military vehicle did Leonardo da Vinci design with a rotating turret?

Leonardo da Vinci designed an armored fighting vehicle commonly called Leonardo’s tank.

The late-fifteenth-century design resembles a conical, turtle-shaped platform covered with armor plates. It was intended to move on wheels and carry several light cannons arranged around its perimeter. A raised central structure could help the crew observe and operate the weapons while remaining protected.

The vehicle is often described as an early tank, but it was not a modern tank in the technical sense. It had no engine, its armor was heavy, and its proposed mechanism has a famous apparent flaw: the internal cranks, as drawn, would make the wheels turn in opposite directions. Some historians think this was an intentional security feature in Leonardo’s notebook, while others regard it as an error.

Leonardo’s vehicle belongs to the history of armored warfare and military engineering. It shows his interest in combining protection, mobility, and concentrated firepower long before tracked tanks appeared during the First World War.