As the vision for the nation's new capital moved forward, a more nettlesome contradiction gained traction.

The new capital was being built in the name of freedom: a nation founded on the idea that "all men are created equal."

(dramatic music) And yet, the labor relied upon to build the Capitol told a very different story.

From the beginning, there was a shortage of free white craftsmen to build Washington DC.

So the commissioners turned to enslavers from Maryland and Virginia, alerting plantation owners that the Capitol would pay to rent their enslaved workers.

The workers, however, were never paid.

The enslavers were paid.

George Washington wanted an elegant, enduring capital.

He wanted the principle buildings to be finished in sandstone, granite, marble.

There was no sandstone nearby.

So enslaved men had to haul sandstone.

Sometimes up to 3,000 pounds, 40 miles from Aquia Creek in Stafford County, Virginia.

Washington viewed sandstone finishes so important that he urged the government to buy Aquia Creek Quarry.

The enslaved men transported the stone by boat up the Potomac, and then carried it to the building site.

The enslaved men worked six days a week in brutal heat and bitter cold.

They lived in rough huts on site.

They survived on meager rations: corn mill, salted meat, sometimes whiskey.

(dramatic music) Disease spread easily: dysentery, smallpox, malaria.

Injury, exhaustion, and death shattered the building of the U.S.

Capitol from the very beginning.

Some ran away.

(dramatic music) Reward notices began to appear across the country for escaped enslaved men.

(dramatic music) Nothing was said until Benjamin Banneker, a free Black man and the one Black man who was paid.

Banneker had used his mathematical, astronomical skills to shape the new capital.

He decided to write to Thomas Jefferson and ask a simple question.

After all, Jefferson was the principal author of the "Declaration of Independence," the one who fashioned a preamble that declared "all men are created equal."

Banneker's question: "how can a nation claim liberty and equality while practicing slavery?"

Banneker writes: - [Banneker] How pitible is it to reflect that although you were so fully convinced of the benevolence of the father of mankind, you should at the same time counteract his mercies in detaining so numerous a part of my brethren under cruel oppression.

- [Narrator] It was a defiant and courageous act.

Jefferson responded: - [Jefferson] Nobody wishes more than I do to see such proofs as you exhibit.

That nature has given to our Black brethren talents equal to those of other colors of men.

- [Narrator] This man who helped give language to the idea of equality still couldn't imagine it applied to Banneker or the almost 700,000 enslaved people in this country.

By 1791, roughly one in five people in the country were enslaved, including 400,000 between Maryland and Virginia combined.

As the Capitol rises and begins to take shape, the tensions on display in the Banneker Jefferson tete-a-tete also rise.

With time, more and more will ask who exactly is included in "We, the people."

While the new Capitol was rising, an unexpected tragedy would throw the building of the capital city once again into turmoil: an event that would ultimately unite the country and finally get the Capitol completed.