BBC iPlayer – Invisible Rome

Hurrah – BBC iPlayer has given us another chance to see historian Professor Michael Scott and TV presenter and Romaphile Alexander Armstrong as they make their way beneath the surface of the Eternal City in their BBC documentary Invisible Rome.

Enjoy the sight of Prof Scott making tufo – not a delicious type of gelato, but Roman concrete and the very thing that has made Rome last an eternity.

In his Naturalis Historia Pliny the Elder reveals the secret of tufo as being the use of seawater. The concrete was used to construct harbours across the Roman Empire and engineers found that the constant exposure to seawater made tufo even stronger –  “a single stone mass, impregnable to the waves and every day stronger.”

Prof Scott does not construct a harbour, sadly, but does test the strength of Roman concrete using his own body mass. The Pantheon is a fine example of the use of tufo – the dome is a miracle of engineering, but more of that later.


Image: Jean-Christophe Benoist, Wikipedia

You can also visit the sole surviving Roman aqueduct beneath Scala Trinità dei Monti (Spanish Steps) which serves the Trevi Fountain with sparkling clear water – and later discover a new use for a bowl of walnuts, which would have been handy in lockdown.


Baths and sewers in Ancient Rome

The intrepid Prof Scott and his eager student Armstrong help map an ancient sewer – and visit the Baths of Caracalla.

Poor Emperor Caracalla is dismissed as a lesser known emperor by Prof Scott, but he certainly knew how to build a public bath.


Emperor Caracalla: I built the best public baths ever, what more do you want? (Image: Wikipedia)

Emperor Caracalla (198-217AD) ruled jointly with his father Septimius Severus from the age of ten – then after his father’s death, with his brother Geta. Caracalla was born Lucius Septimius Bassianu in 188AD and was also known as Antoninus, before settling on the name that would make his public baths famous all the world over.



The documentary is now several years old, but Scott and Armstrong march about the sewer system clad in PPF2.5 face masks, revealing such gems as various uses for urine – you can clean your teeth with it and the ammonia in urine is also useful in laundry. Who knew?

Building a Dome in Rome 


The Pantheon (Image: Pexels)

Back out of the sewer, Rome is as lovely as ever, even in a thunderstorm and with torrential rain pouring through the dome of the Pantheon – and now you know all about the strength of Roman concrete, you can find out the secrets of how this miraculous dome stays standing and the miracle of engineering that supports it.

Mithras worship in Rome


We also visit a temple dedicated to the cult of Mithras – a bull slaying religion much favoured by men bonding, a bit like an ancient Chamber of Commerce. There are similarities to Christianity and also Middle Eastern religions. In London, there is a Mithras Temple restored right in the heart of the City of London. In Rome, there are 35 Mithras Temples, so that is a lot of male bonding.

Catacombs in Rome 


Image Pixabay

Finally, we take a trip to the Catacombs – not everyone’s cup of Pinot Grigio, but Scott and Armstrong are so excited about the innovative use of a space that resulted from excavation to make concrete that we barely notice the incumbents.

It is all about concrete and decoration – including an image of the Menorah painted on one wall to denote a Jewish burial vault. The Jewish community in Rome is one of the oldest in the world outside Jerusalem – and Julius Caesar was known as a great friend to the Jewish community, who mourned him after his murder.

If you love ancient history or Rome, this documentary is the most fun you can have underground with your clothes on. Armstrong touches on the other ways the Romans found when he visits a Roman bath house. Avert your eyes now.

You can enjoy Invisible Rome on BBC iPlayer.

Buon viaggio!


More info:

Take a virtual trip on YouTube to the virtual Terme di Caracalla (Baths of Caracalla) as they would have been in Ancient Rome.

For more info on Mithras, See my post on the Mithraeum in London.


The Mithraeum in London – I discovered (by asking too many questions!) that the plate you can see on the ground marks the spot where, above ground, the temple was first discovered near Mansion House in the City of London. It now lies beneath news and media giant Bloomberg’s new offices.


All images A. Meredith except where stated.

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