What if Everybody Lived Underwater?

If everybody lived underwater, then people would live in enormous glass domes. The glass would have to be in really thick layers and there would have to be special openings for transportation and shippings between the glass domes. Advanced engineering would be needed for the glass domes to be able to provide a natural mixture of oxygen, nitrogen, carbon dioxide, and other gases. There would be special buildings, from which some are designed for manufacturing, some would be for living inside, and others are office buildings.

Children would learn to swim at an early age. They will play underwater games outside similar to those they played today. They would go to school normally like the kids today.