Forty Feet Beneath the East River

When engineer Washington Roebling began constructing the Brooklyn Bridge in 1870, the most critical work happened where no one could see it. Workers descended into massive pressurized wooden boxes called caissons, lowered to the bottom of the East River, and dug through layers of mud, rotting timber, and glacial stone to reach solid bedrock. The work was grueling, dangerous, and inglorious.…