"It's a perfect day to walk across the Brooklyn Bridge," Paul said.
He looked up at the enormous bridge that connected two very busy parts of New York City—Brooklyn and Manhattan.
The bridge was pretty old now.
But with its tall stone towers and strong-looking cables, it was still an amazing sight above the East River.
"Dad, who built this bridge?" Paul asked.
"A man named John Roebling," his father answered.
"Now Brooklyn and Manhattan are part of the same city—New York.
But they used to be two different cities.
In the 1800s boats would bring people back and forth across the East River to work, shop, or visit friends.
The river was sometimes rough, and the boats were often late.
One day John was on one of those boats with his son, and he got the idea to build a suspension bridge across the river.
Many people said it couldn't be done.
But one winter the East River froze, and the boats couldn't get through.
People from Brooklyn couldn't get to work in Manhattan.
Finally it was decided that a bridge should be built, connecting the two places."
"Was John Roebling an engineer like you?" asked Paul.
"Yes, he was. His son, Washington, was an engineer too.
In 1869 they started to work on the bridge together.
But sadly, a freak accident happened.
While John Roebling was on the Brooklyn side of the river, his foot got caught in the dock.
An incoming boat crashed into the dock, injuring him badly.
He died a month later. So Washington took over."
"Washington must have been sad when his father died," murmured Paul.
"Yes, he and his father were very close.
But Washington was ready for the job.
He started working right away, digging deep under the river mud to create supports for the two bridge towers.
This almost cost him his life."
Paul gasped. "You mean, Washington almost died too?"
"Yes, he designed something called a caisson to use for the underwater project.
These caissons, which prevented the water from flooding the work area, were filled with compressed air.
And at the time, people didn't realize that working in compressed air can cause caisson disease, or decompression sickness.
That's a dangerous condition that results from gas bubbles forming inside the body.
Caisson disease affected Washington's nervous system, paralyzing him for a time and causing him great pain.
Some members of his work crew even died from the illness!
Washington never returned to the bridge, but he continued to manage the project.
Imagine this—he used a telescope to watch the progress of the bridge construction from his home in Brooklyn!"
"Wow. It sounds like he was pretty sick—how could he manage everything from home?" Paul asked.
"Good question," his father said. "Washington's wife, Emily, helped him.
She wrote his letters and helped with planning the work.
She served as his eyes and ears, and delivered all his orders to the workers.
She even studied complicated mathematics to learn more about building!
Soon she earned the respect of everyone involved in the project.
If it weren't for her, the Brooklyn Bridge probably wouldn't have been finished."
Paul's father pointed to the bridge towers.
"When those towers were finished, they were 25 stories high, taller than any of the other buildings around them.
Can you imagine that?"
Paul looked at the city skyline.
All the huge skyscrapers made the bridge towers look small now.
He tried to imagine how different the city must have looked back then.
"See those four main cables that run along the top from one tower to the other?" his father went on.
"Can you spot all the wires hanging down from them?
John Roebling invented their material, which is called wire rope.
The wire rope is made of steel, so it is strong and can easily be bent into any shape.
The Brooklyn Bridge was the first bridge where it was used.
But those slanted supports were Washington's idea.
He added them to make sure the bridge was safe."
"How long did it take to build the bridge?" asked Paul.
"Fourteen years," answered his father. "It was an amazing undertaking.
When it was finished, it was the longest suspension bridge in the world.
At the opening day ceremony in 1883, Emily Roebling was given the honor of being the first person to cross the bridge.
She rode in a horse and carriage from the Brooklyn side to the Manhattan side.
The workers all cheered as she went by."
"Her husband must have been proud," said Paul.
"Yes, it was his idea.
Crowds lined the streets of Manhattan and Brooklyn, and hundreds of ships were packed into the East River.
On the Manhattan side, the president of the United States waited with the governor and the mayor of New York City.
Then they met Emily and they all walked across the bridge together.
After the ceremony they went to the Roebling house to honor Washington and his father.
There was a grand show of fireworks that night.
It was the greatest celebration ever held in America up until that time."
"That sounds pretty cool," said Paul.
His father agreed with a nod.
"I'd like to help build a bridge like that one day," said Paul.
His father beamed.
"The Brooklyn Bridge inspired the building of many other bridges, allowing people to travel easily to many new places.
It was seen as the greatest engineering achievement of the nineteenth century."
"My teacher said the Brooklyn Bridge is a true American landmark."
Paul grabbed his father's arm.
"Come on, Dad! Let's see how fast we can get to the other side!"