Which Leonardo da Vinci invention was a mechanical lion that could walk and open its chest?

Leonardo da Vinci’s mechanical lion was an automaton designed to walk and open its chest.

The lion is traditionally associated with a 1515 celebration in Lyon, where it was reportedly presented to King Francis I of France. Accounts say that the mechanical animal moved forward and opened its chest to reveal lilies, symbols associated with Florence and the French monarchy. The story connects Leonardo with court spectacles as well as engineering.

The original machine has not survived, so details of its mechanism cannot be inspected directly. Later reconstructions are based on historical descriptions and Leonardo’s reputation for designing automata. Because the evidence is incomplete, claims about exactly how far it walked or how its internal parts operated should be treated cautiously.

The lion is often confused with Leonardo’s mechanical knight. The knight is a human-shaped automaton associated with a 1495 Milanese celebration; the lion is the animal-shaped device linked with Francis I.