Well, little one, a long time ago people wanted to explore what was underwater in the sea. So they had to find a way to breathe underwater and move around.
First, they used things like hollow reeds and animal skins to hold air while they explored underwater. Then, they invented diving bells that were like small cages that people could lower down into the water while they held their breath.
Later on, people learned how to make diving suits that could help them breathe underwater. These suits were made of heavy metal and had a hose that went to the surface so they could breathe fresh air from above. People could walk along the bottom of the sea wearing these suits, but they could only stay down for a short time.
Today, we have much more advanced diving equipment like scuba gear. This allows us to breathe underwater with special tanks of air that are strapped to our backs. Scuba diving has opened up a whole new world of exploration for us to see all the beautiful sea creatures and plants that live in the oceans.
So, you see, underwater diving has come a long way since people first started exploring the seas.