Look up. You're standing beneath one of the Brooklyn Bridge towers. Two hundred seventy-six feet of granite and limestone. When these were built, they were the tallest structures in the Western Hemisphere. Taller than every building in Manhattan. Taller than every building in Brooklyn.
And underneath the one on the Manhattan side — the one closest to where you just were — there is sand. Not bedrock. Sand. Ninety thousand tons of granite tower, sitting on packed sand, for over a hundred and forty years.
That's not an accident. That's a decision. And it starts with the caissons.
To build a tower in a river, you need to dig down to something solid. The way they did this in eighteen seventy was to build a massive wooden box — open at the bottom, sealed at the top — sink it to the riverbed, and pump compressed air inside to keep the water out. Then men climbed down into this box and dug.
These boxes were enormous. A hundred and sixty-eight feet long. A hundred and two feet wide. That's
roughly half a city block. Flipped upside down. At the bottom of a river.
Inside, the air pressure was three to four times normal. The temperature hit eighty degrees. Workers stripped to the waist within minutes. A fifteen-year-old kid named Frank Harris — who later became a famous writer — worked in the caissons. His account is the best we have.
He wrote: the pain stabbed my ears. The sweat was
