eli5: How did people build bridges over deep and/or dangerous water if they didn’t have the equipment to go under water?

Question

eli5: How did people build bridges over deep and/or dangerous water if they didn’t have the equipment to go under water?

In: 22

Answer 1

There are several answers here that are correct, but they used a different method from any of them when the built the Brooklyn Bridge. They built a wooden “room” larger than the bridge supports, and submerged it, and essentially just made two big square holes in the river to work in.