The golden gate bridge and many others were built by working in dry "bubbles". An inverted dome on the sea floor was filled with air so the workers could work o

The golden gate bridge and many others were built by working in dry "bubbles". An inverted dome on the sea floor was filled with air so the workers could work on the seafloor pretty much the same as on the ground outside. I don't know how they worked under that air pressure. I guess they had to decompress like any diver.