Construction of the Brooklyn Bridge had begun out of sight, in wooden caissons, enormous bottomless boxes in which men dug away at the river bottom. As the caissons sunk deeper into bedrock of New York, massive stone towers were built on top of them.
The towers, when completed, rose nearly 300 feet above the water of the East River. In the time before skyscrapers, when most buildings in New York were two or three stories, that was simply astounding.
In this stereograph, a double-photograph which would appear three-dimensional when viewed with a special device, the towers have been completed and the only connection between them is a narrow wooden footbridge strung high above the river.
The footbridge was put in place in early 1877 for the use of the bridge workers, but daring people who obtained special permission could walk across.