You're in a room the size of a closet with your entire family.

You can't see a thing, but you can hear on smell everything, every breath, every sneeze it, every cough that hits your face.

This is life in 1/19 century city.

There's a There's a story off 19th century American history, which is about progress, the rise of America to becoming a great economic power.

But there's a pretty grim underbelly to that story on that is a really shocking rate of death to infectious diseases.

America in the 17 hundreds is, to a large extent, a country off Hamlets and villages and small towns with a few cities which are slowly growing.

Come the 18 hundreds, cities like Boston and New York are doubling and doubling again.

Technological innovation was thriving titans of business like Rockefeller and Carnegie, growing industries at unprecedented rates.

Railroads were transporting people in things faster.

Machines were making things more efficiently than humans ever had in history.

This was, quite literally a revolution.

Tons of new jobs were created, but here's the thing.

The city's weren't ready for all those people.

So places like New York City ended up packing these newcomers into cheap apartments or tenements.

They were small and rarely had windows, so there was no light or ventilation houses air overcrowded.

They're working in factories there, breathing on one another.

They're contaminating one another with their germs and also with feces.

That's right, feces.

That's because there weren't proper sanitation or sewer systems or clean water supplies very rapidly.

People are starting to drink water, which contains feces from their neighbors.

There are a number of diseases that claimed a lot of lives.

The most serious were respiratory illnesses.

On the biggest killer of all was tuberculosis.

Tuberculosis killed one in seven in the United States and Europe.

At this point, people came to suspect that their living conditions influence their health.

They began to argue.

If you want to combat diseases, you've simply got to clean up the slum areas.

In fact, in New York in the 18 thirties, they have people sweep the streets, and this has barely being done for decades, and they're amazed to find that underneath A with the mock of the filth on the decomposing animal bodies, they were actually Coble servants.

They're all doing this because they believe in my asthma's these gasses that rise up from decomposing matter, which they believe somehow cause sickness.

But the effort to clean cities got a major push in the late 19th century, when doctors and scientists were able to prove that diseases were not caused by my asthma's but by germs.

One of those doctors was Robert Coke.

Robert Cock was a German general practitioner who, in his spare time when not treating patients, devoted endless hours to investigating disease.

Under the microscope.

He discovered that specific germs caused specific diseases, but he's probably best known for his work in tuberculosis.

He discovered the germ responsible and found that it's transmitted through the air.

Now that people realize what causes infectious disease, they have every incentive, making sure that people have clean water.

Do you wash your hands?

You wash away many of the disease carrying smudges you may have picked up on.

They have sewage pipes to take away the affluence.

What this leads to is large scale civil engineering projects across America.

Due to the improved access to clean water in the first few decades of the 20th century, US cities saw an estimated 50% drop in mortalities laws were also passed to reform housing in the cities to ensure residents had sufficient light and proper ventilation in their homes.

E In less than 20 years, the death rate from tuberculosis plummeted from one out of every seven.

Two more like one in 1000 in the United States.

Robert Coat even got a Nobel Prize for the impact of his tuberculosis research.

Life generally was getting better and better for Americans knowing that germs cause disease was a significant component off about.