Dan wrote an entry for the BBC TV Blog on his series Filthy Cities:

When the BBC got in touch with me and suggested a series about the history of filth I was suitably nervous.

In Filthy Cities, they wanted a series which explored the idea that we humans create a huge amount of waste that, if left untreated, can destroy us.

By looking at how human societies have overcome the problem of their own filth we can understand a huge amount about the changes that have taken place in our society: the rise of the mega-city, lengthening life expectancies, less disease and the far better sanitation that we take for granted in the UK now.

I said yes, knowing it would be an adventure and that I would learn a huge amount about a part of history that I do not know enough about.

Filth may be less glamorous than kings, queens, castles and politics but I knew it would turn out to be just as fascinating and arguably more important.

Each city – London, Paris and New York – had not only to have had a filthy past but had to have been instrumental in developing modern systems of waste management: sewers, government regulation or scientific breakthroughs.

For the first time in history the majority of humanity now lives in cities. These three cities tell us how this became possible.

During the series – which really is immersive history at its best – I spent time in sewers, studied the skeleton of a plague victim, shovelled tons of horse poo, was bitten by a rat, fed to leeches, and used dog poo and urine to treat leather hides.

I used rancid meat to make mince, cleaned an apartment that had not been cleaned for thirty years, butchered a pig and used its entrails to make sausages, and was eaten alive by bed bugs and lice.

It was a busy summer and friends could not believe what I was getting up to.

I had great fun and learned a good deal. Perhaps my most important realisation was simply the debt that we owe the people who get rid of our waste and ensure we have clean water.

Without sewage works or bin collectors, we would drown in our waste within days.

They make life in big cities possible. That is why the absence of these services in the past has led to massive outbreaks of disease or even revolution.

One of my favourite experiences was driving an electric car around New York. It was 100 years old.

Incredibly many of the early cars were electric. It was only when Henry Ford successfully produced the Model T that the combustion-engined car became the obvious choice for millions of people.

I came very close to scraping this precious vehicle and I think the owner seriously regretted letting me use it.

People often ask me, now that I’ve been through it all, whether I am permanently scarred.

I must say that I have had quite enough of the smell of raw sewage, but in fact it has made me more interested in the hidden realities of our existence.

Thanks to Filthy Cities I peeled back a bit of the sanitised veneer of our society and it simply fired my enthusiasm to learn more.

I hope you really enjoy the series, which peels back the layers of time to give you the opportunity to experience our filthy past.