Leonardo da Vinci sketched a diving suit intended to let a person breathe and work underwater.
His design, recorded in the early 16th century, included a mask, breathing tubes, and a system connected to the surface. The concept also included a means for the diver to collect urine, reflecting Leonardo's attempt to think through the practical problems of a prolonged underwater mission. Some versions are associated with a rigid helmet and a floating support structure.
Leonardo appears to have considered military uses, including underwater activity near enemy ships. However, there is no reliable evidence that he built and tested the suit or that it was used in a historical naval operation. The idea belongs to a broader group of Leonardo's designs that combined anatomy, fluid mechanics, and military engineering.
The sketch should not be confused with a modern scuba suit. Modern scuba equipment uses compressed-gas cylinders, regulators, and carefully designed buoyancy systems. Leonardo's design depended mainly on air supplied from above, so it is closer in principle to a surface-supplied diving system.