How Modern London Rose From Roman Ruins

London is actually two cities,

one built on top of the other.

Before there was London, there was Londinium,

an outpost of the Roman Empire that was founded right here

in the heart of modern London.

And it's from this ancient city, Londinium,

that modern London takes its name and so much more.

And there's still evidence

of London's 2,000 year old Roman origins all over the city

if you know where to look.

I'm Nick Potts, I'm an architect,

and today we're taking a walking tour

of London's Roman origins.

[soft upbeat music]

It's not just the name London that comes from ancient Rome.

The layout of the city,

even including the location of London Bridge,

is directly connected from the original plan

of Roman Londinium.

And even today, pieces of the ancient city continue

to be discovered, giving us more clarity about how the rise

and the fall of ancient Londinium shaped

and continues to shape the modern city of London.

So if all roads lead to Rome,

let's start at the most important intersection

of ancient Londinium.

[soft bright music]

Right now we're standing at the most important intersection

of Roman Londinium

because underneath our feet is the starting point

of every Roman city, the Roman Forum.

As Rome expanded,

every new city they built was designed as a grid,

and at the center of each grid was what's called the Forum.

The Forum in a Roman city was both a marketplace

for commerce, but also a marketplace of ideas.

It was a place for politics, legal proceedings,

and civic gatherings of all kinds.

And in every Roman city,

the Forum was located near the intersection

of two major roads,

which were called the Cardo and the Decumanus.

The Cardo was the primary market street,

and the Decumanus was the primary military street,

connecting the towns throughout the empire.

And this phrase, All roads lead to Rome,

has something to do with that.

As the empire was expanding,

symbolically they wanted there to be a street

that connected these provincial outposts

and peripheral towns back to the heart of the empire,

which was Rome.

This is the intersection of Gracechurch Street

and Lombard Street where it transitions to Fenchurch.

And in Londinium, this is where the Roman Forum was.

In a Roman outpost,

the Decumanus was primarily east west,

and the Cardo was north south.

And if you look at the map of London today,

you can still see this intersection of the Cardo,

essentially at Gracechurch Street leading down

to London Bridge,

which was in the same location

that London Bridge currently is, more or less.

And in the case of Londinium,

where the settlement was located directly north

of the river Thames and the important port,

which is the reason why the Romans decided

to put this place here,

the Cardo was as crucial link between the river

and all the trade that happened on it

and the main marketplace.

So the commerce in Roman Londinium ran north to south

on the Cardo and various streets parallel to it.

And as a city that's primarily a medieval settlement or was,

London has a fairly ad hoc informal grid.

But in this area in particular,

you can see the ghost of the grid of Roman Londinium,

which is torn down in AD 450.

It's fairly unique in the older parts of London

to see this grid structure,

and that's a direct ancestor of the Roman settlement

that existed here before.

And you can see a ghost of that today

in the names of the streets that currently exist

between the Forum location and the river Thames.

You see Pudding, which talked about meat trade.

You see Fish Hill that talked about the movement

of fish up and down.

And even though these uses came back in the medieval city

after Londinium was abandoned,

it almost came back from the dead

when the site was resettled.

In fact, the Romans were the ones

to first build a bridge across the Thames.

And the location of that bridge currently can be seen

in the street grid next to it.

This original bridge would've been located parallel

to where today's London bridge is

and directly in alignment with the Cardo

and connected to the Forum.

But we don't need to look

at the map to figure out

where the Roman Forum would've been located in Londinium

because in 2025,

archeologists drilled a massive hole

into the floor of an office building

and uncovered the foundations

of the most important building in Roman Londinium.

[upbeat music]

Behind me is Leadenhall Market,

one of London's most historic markets,

and also the site of some

of London's most newly rediscovered ruins.

What was recently found underneath this building

actually reconfirmed the location

of Roman London's most important building, the Basilica.

We're just down the street here from the center

of the Forum on nearly the exact site

of the original Roman Basilica.

In a Roman city, the Basilica was always located

on one end of the Forum

and was a space used for political, economic,

and administrative purposes such as court proceedings.

Leadenhall Market has existed in this location

since roughly the 1300s,

but the current structure was built in the late 1800s,

designed by Horace Jones.

And the building that he designed in the 19th century

is strikingly similar to the Roman building

that existed here nearly 2,000 years ago.

The word basilica brings to mind a religious building,

a Christian Church, and that's no accident.

A lot of early Christian churches took over the sites

of Roman Basilicas and their plan,

which was a large central nave and side aisles.

And the formerly secular,

kind of multi-purpose use of a Roman Basilica was co-opted

by a Christian typology.

However, the mall or the market took

on a similar sort of name.

And so it's an interesting irony that the Leadenhall Market

essentially co-opted the Basilica plan

with a large vaulted, central nave

and its side aisles for the markets and shops,

which is an almost reappropriation of this Roman space plan.

And it's an amazing coincidence that this building type,

this market that's co-opted the type form

of a Roman Basilica was reconstructed

in the 19th century directly over

and in alignment with the original Roman Basilica.

And this was done without the architect likely knowing

about the location or frankly the shape

of the original Roman Basilica.

And while the Basilica is the most recent rediscovery

in Roman London, it's far from the only one.

This site was carefully uncovered by archeologists

during the construction of a building next door.

But many of the ruins

of Roman London would've never been discovered

had it not been for the bombings during the blitz

of World War II.

[upbeat music]

We're standing in the Barbican Centre

and the round tower you can see

behind me was quite possibly the oldest piece

of Roman construction within Londinium.

The Barbican is a brutalist building complex

that helped to inject modern architecture

into the fabric of historic London.

During the blitz of World War II,

this area was heavily bombed

and while the entire city

that had been built up over the several thousand years

was largely destroyed,

what was revealed was a lot of Roman foundations

and the basis for the original city.

Before Roman Londinium,

there was just a fort on this location

and the location marked by that tower,

even though the tower has been built up on

and modified over the years,

is the location of the northern most corner of that fort.

This was far from the only place that was bombed

during the blitz

and throughout the historic core of London,

there were little bits and pieces that were discovered

as almost treasures that emerged despite all of the trauma

of the bombing.

Parts of a fresco were discovered underneath Lime Street,

the foundations of a massive building

under the Canon Street Station

and the Temple of Mithras,

which is currently on exhibition

under the new Bloomberg headquarters.

And similar to what was done with the Mithraeum,

where it was really showcased as part of the new building,

the Barbican takes that to an extreme

and creates an entire landscape built around the fragments

of its Roman past.

And this is really the story of London.

And you can see this all along the former Roman wall,

these different layers, the Roman layer of wall,

the medieval constructions both on top of

and incorporating the wall

and new buildings popping up usually

around it rather than on top of it, showcasing it.

So if you look around us

in these very kind of openly modernist buildings,

there are bits of the language of the Roman architecture

that originally happened here.

You see brick, you see arches,

and they're reinterpreted in a very kind of contemporary,

almost inverted way.

You see these fragments of almost like a Roman concrete.

So these buildings are riffing on the language

of Roman architecture without explicitly copying it.

And this is really what modernism

of this period was trying to do.

It was trying to monumentalize the past

and create a new language that was fitting for modern times

as opposed to previous neoclassical revivals

that were explicitly copying and mimicking the Romans.

The Barbican is a very modern mixed use complex

with schools, with housing, and art centre,

public space and old church.

And there's a very kind of modernist urban planning sort

of vision for rebuilding the city that its architects,

Chamberlin, Powell and Bon,

utilized to its utmost.

And this is really a unique space in London,

primarily because of the blitz.

The city had an opportunity

to build something really at the scale

of large modernist urban planning.

And the trauma of the war created in its horrific aftermath,

an opportunity for London to experiment a bit

with 20th century urban planning ideals.

And the Barbican represents this

in both its program, its style and its form.

This is just a small piece of London and its Roman origins.

Let us know what other cities we should explore

in comments below.