Which Leonardo da Vinci invention was an early human-powered diving suit?

Leonardo da Vinci designed an early diving suit. His concept included a sealed leather suit, a mask, breathing tubes, and a system intended to let a diver remain underwater.

The design is associated with Leonardo’s studies of military engineering and underwater operations in the early sixteenth century. Some drawings show air being supplied through tubes connected to a floating apparatus. Other versions included a bag or reservoir for air and features intended to help the diver move and control buoyancy.

Leonardo’s suit was a design concept rather than a documented working invention. It also should not be confused with modern scuba equipment, which uses a compressed-air cylinder and regulator. The historical importance of the sketch is that it combines practical diving requirements—breathing, vision, movement, and protection—centuries before reliable underwater equipment existed.