Leonardo da Vinci designed a diving suit intended to let a person breathe underwater.
His concept included a full suit, a mask, and tubes leading to the surface so that air could reach the diver. The design appears in Leonardo’s studies of water and military engineering, where underwater operations might have been used to damage enemy vessels.
Leonardo also considered a breathing arrangement with a bag or air reservoir, but the surviving drawings do not establish a single complete, tested apparatus. The design was never proven in Renaissance conditions. It is best described as an early diving-suit concept rather than a modern scuba system or a true submarine.